diff --git a/abaplint_exercises.json b/abaplint_exercises.json
index c9868c9..ae230f4 100644
--- a/abaplint_exercises.json
+++ b/abaplint_exercises.json
@@ -84,19 +84,7 @@
     "check_syntax": true,
     "check_text_elements": true,
     "check_transformation_exists": true,
-    "class_attribute_names": {
-      "exclude": [],
-      "severity": "Error",
-      "patternKind": "required",
-      "ignoreNames": [],
-      "ignorePatterns": [],
-      "ignoreExceptions": true,
-      "ignoreLocal": true,
-      "ignoreInterfaces": false,
-      "statics": "^G._.+$",
-      "instance": "^M._.+$",
-      "constants": ""
-    },
+    "class_attribute_names": false,
     "cloud_types": true,
     "colon_missing_space": true,
     "commented_code": {
@@ -516,11 +504,7 @@
     "tabl_enhancement_category": true,
     "try_without_catch": true,
     "type_form_parameters": true,
-    "types_naming": {
-      "exclude": [],
-      "severity": "Error",
-      "pattern": "^TY_.+$"
-    },
+    "types_naming": false,
     "uncaught_exception": true,
     "unknown_types": true,
     "unreachable_code": true,
diff --git a/abaplint_solutions.json b/abaplint_solutions.json
index 7a8123b..4426c83 100644
--- a/abaplint_solutions.json
+++ b/abaplint_solutions.json
@@ -84,19 +84,7 @@
     "check_syntax": true,
     "check_text_elements": true,
     "check_transformation_exists": true,
-    "class_attribute_names": {
-      "exclude": [],
-      "severity": "Error",
-      "patternKind": "required",
-      "ignoreNames": [],
-      "ignorePatterns": [],
-      "ignoreExceptions": true,
-      "ignoreLocal": true,
-      "ignoreInterfaces": false,
-      "statics": "^G._.+$",
-      "instance": "^M._.+$",
-      "constants": ""
-    },
+    "class_attribute_names": false,
     "cloud_types": true,
     "colon_missing_space": true,
     "commented_code": {
@@ -516,11 +504,7 @@
     "tabl_enhancement_category": true,
     "try_without_catch": true,
     "type_form_parameters": true,
-    "types_naming": {
-      "exclude": [],
-      "severity": "Error",
-      "pattern": "^TY_.+$"
-    },
+    "types_naming": false,
     "uncaught_exception": true,
     "unknown_types": true,
     "unreachable_code": true,
diff --git a/config.json b/config.json
index 348b444..97ca961 100644
--- a/config.json
+++ b/config.json
@@ -60,6 +60,14 @@
         "practices": [],
         "prerequisites": [],
         "difficulty": 1
+      },
+      {
+        "slug": "clock",
+        "name": "Clock",
+        "uuid": "ac4e5fb1-1e7c-461d-b2df-1abfd88d8c8a",
+        "practices": [],
+        "prerequisites": [],
+        "difficulty": 1
       }
     ]
   },
diff --git a/exercises/practice/clock/.docs/instructions.md b/exercises/practice/clock/.docs/instructions.md
new file mode 100644
index 0000000..a1efc78
--- /dev/null
+++ b/exercises/practice/clock/.docs/instructions.md
@@ -0,0 +1,7 @@
+# Instructions
+
+Implement a clock that handles times without dates.
+
+You should be able to add and subtract minutes to it.
+
+Two clocks that represent the same time should be equal to each other.
diff --git a/exercises/practice/clock/.meta/config.json b/exercises/practice/clock/.meta/config.json
new file mode 100644
index 0000000..73a867c
--- /dev/null
+++ b/exercises/practice/clock/.meta/config.json
@@ -0,0 +1,10 @@
+{
+  "blurb": "Clock",
+  "authors": ["mbtools"],
+  "contributors": [],
+  "files": {
+    "solution": ["zcl_clock.clas.abap"],
+    "test": ["zcl_clock.clas.testclasses.abap"],
+    "example": [".meta/zcl_clock.clas.abap"]
+  }
+}
\ No newline at end of file
diff --git a/exercises/practice/clock/.meta/zcl_clock.clas.abap b/exercises/practice/clock/.meta/zcl_clock.clas.abap
new file mode 100644
index 0000000..582940f
--- /dev/null
+++ b/exercises/practice/clock/.meta/zcl_clock.clas.abap
@@ -0,0 +1,54 @@
+CLASS zcl_clock DEFINITION
+  PUBLIC
+  CREATE PUBLIC.
+
+  PUBLIC SECTION.
+
+    METHODS constructor
+      IMPORTING
+        !hours   TYPE i
+        !minutes TYPE i DEFAULT 0.
+    METHODS get
+      RETURNING
+        VALUE(result) TYPE string.
+    METHODS add
+      IMPORTING
+        !minutes TYPE i.
+    METHODS sub
+      IMPORTING
+        !minutes TYPE i.
+
+  PRIVATE SECTION.
+
+    DATA clock TYPE t.
+
+ENDCLASS.
+
+
+
+CLASS zcl_clock IMPLEMENTATION.
+
+
+  METHOD add.
+    clock = clock + minutes * 60.
+  ENDMETHOD.
+
+
+  METHOD constructor.
+    " Clock is number of seconds
+    clock = hours * 60 * 60 + minutes * 60.
+  ENDMETHOD.
+
+
+  METHOD get.
+    " hh:mm:ss
+    result = |{ clock TIME = ISO }|.
+    " return only hh:mm
+    result = result(5).
+  ENDMETHOD.
+
+
+  METHOD sub.
+    clock = clock - minutes * 60.
+  ENDMETHOD.
+ENDCLASS.
diff --git a/exercises/practice/clock/zcl_clock.clas.abap b/exercises/practice/clock/zcl_clock.clas.abap
new file mode 100644
index 0000000..b7fb710
--- /dev/null
+++ b/exercises/practice/clock/zcl_clock.clas.abap
@@ -0,0 +1,49 @@
+CLASS zcl_clock DEFINITION
+  PUBLIC
+  CREATE PUBLIC.
+
+  PUBLIC SECTION.
+
+    METHODS constructor
+      IMPORTING
+        !hours   TYPE i
+        !minutes TYPE i DEFAULT 0.
+    METHODS get
+      RETURNING
+        VALUE(result) TYPE string.
+    METHODS add
+      IMPORTING
+        !minutes TYPE i.
+    METHODS sub
+      IMPORTING
+        !minutes TYPE i.
+
+  PRIVATE SECTION.
+
+* add solution here
+
+ENDCLASS.
+
+
+
+CLASS zcl_clock IMPLEMENTATION.
+
+  METHOD add.
+* add solution here
+  ENDMETHOD.
+
+
+  METHOD constructor.
+* add solution here
+  ENDMETHOD.
+
+
+  METHOD get.
+* add solution here
+  ENDMETHOD.
+
+
+  METHOD sub.
+* add solution here
+  ENDMETHOD.
+ENDCLASS.
diff --git a/exercises/practice/clock/zcl_clock.clas.testclasses.abap b/exercises/practice/clock/zcl_clock.clas.testclasses.abap
new file mode 100644
index 0000000..65eea7e
--- /dev/null
+++ b/exercises/practice/clock/zcl_clock.clas.testclasses.abap
@@ -0,0 +1,303 @@
+CLASS ltcl_clock DEFINITION FOR TESTING RISK LEVEL HARMLESS DURATION SHORT FINAL.
+
+  PRIVATE SECTION.
+    DATA cut TYPE REF TO zcl_clock.
+
+    METHODS:
+      on_the_hour FOR TESTING,
+      past_the_hour FOR TESTING,
+      adding_a_few_minutes FOR TESTING,
+      adding_zero_minutes FOR TESTING,
+      adding_over_an_hour FOR TESTING,
+      adding_more_than_two_hours_w_c FOR TESTING,
+      adding_more_than_two_days FOR TESTING,
+      wrap_around_at_midnight FOR TESTING,
+      subtract_minutes FOR TESTING,
+      subtract_more_than_two_hours FOR TESTING,
+      subtract_more_than_two_hours_w FOR TESTING,
+      subtract_more_than_two_days FOR TESTING,
+      wrap_around_backwards FOR TESTING,
+      wrap_around_day FOR TESTING,
+      wrap_around_day_backwards FOR TESTING,
+      equivalent_clocks FOR TESTING,
+      inequivalent_clocks FOR TESTING,
+      equivalent_clocks_1 FOR TESTING,
+      equivalent_clocks_2 FOR TESTING,
+      equivalent_clocks_3 FOR TESTING,
+      equivalent_clocks_4 FOR TESTING,
+      equivalent_clocks_5 FOR TESTING,
+      equivalent_clocks_6 FOR TESTING,
+      hours_rollover FOR TESTING,
+      minutes_rollover FOR TESTING,
+      hours_and_minutes_rollover FOR TESTING,
+      negative_hours_rollover FOR TESTING,
+      negative_minutes_rollover FOR TESTING,
+      negative_hours_and_minutes FOR TESTING.
+
+ENDCLASS.
+
+CLASS ltcl_clock IMPLEMENTATION.
+
+  METHOD on_the_hour.
+    cut = NEW zcl_clock( 8 ).
+
+    cl_abap_unit_assert=>assert_equals(
+        exp = '08:00'
+        act = cut->get( ) ).
+  ENDMETHOD.
+
+  METHOD past_the_hour.
+    cut = NEW zcl_clock( hours   = 11
+                         minutes = 9 ).
+
+    cl_abap_unit_assert=>assert_equals(
+        exp = '11:09'
+        act = cut->get( ) ).
+  ENDMETHOD.
+
+  METHOD adding_a_few_minutes.
+    cut = NEW zcl_clock( 10 ).
+
+    cut->add( 3 ).
+
+    cl_abap_unit_assert=>assert_equals(
+        exp = '10:03'
+        act = cut->get( ) ).
+  ENDMETHOD.
+
+  METHOD adding_zero_minutes.
+    cut = NEW zcl_clock( hours   = 6
+                         minutes = 41 ).
+
+    cut->add( 0 ).
+
+    cl_abap_unit_assert=>assert_equals(
+        exp = '06:41'
+        act = cut->get( ) ).
+  ENDMETHOD.
+
+  METHOD adding_over_an_hour.
+    cut = NEW zcl_clock( 10 ).
+
+    cut->add( 61 ).
+
+    cl_abap_unit_assert=>assert_equals(
+        exp = '11:01'
+        act = cut->get( ) ).
+  ENDMETHOD.
+
+  METHOD adding_more_than_two_hours_w_c.
+    cut = NEW zcl_clock( hours   = 0
+                         minutes = 45 ).
+
+    cut->add( 160 ).
+
+    cl_abap_unit_assert=>assert_equals(
+        exp = '03:25'
+        act = cut->get( ) ).
+  ENDMETHOD.
+
+  METHOD adding_more_than_two_days.
+    cut = NEW zcl_clock( hours   = 1
+                         minutes = 1 ).
+
+    cut->add( 3500 ).
+
+    cl_abap_unit_assert=>assert_equals(
+        exp = '11:21'
+        act = cut->get( ) ).
+  ENDMETHOD.
+
+  METHOD wrap_around_at_midnight.
+    cut = NEW zcl_clock( hours   = 23
+                         minutes = 30 ).
+
+    cut->add( 60 ).
+
+    cl_abap_unit_assert=>assert_equals(
+        exp = '00:30'
+        act = cut->get( ) ).
+  ENDMETHOD.
+
+  METHOD subtract_minutes.
+    cut = NEW zcl_clock( 10 ).
+
+    cut->sub( 90 ).
+
+    cl_abap_unit_assert=>assert_equals(
+        exp = '08:30'
+        act = cut->get( ) ).
+  ENDMETHOD.
+
+  METHOD subtract_more_than_two_hours.
+    cut = NEW zcl_clock( hours   = 6
+                         minutes = 15 ).
+
+    cut->sub( 160 ).
+
+    cl_abap_unit_assert=>assert_equals(
+        exp = '03:35'
+        act = cut->get( ) ).
+  ENDMETHOD.
+
+  METHOD subtract_more_than_two_hours_w.
+    cut = NEW zcl_clock( hours   = 6
+                         minutes = 15 ).
+
+    cut->add( -160 ).
+
+    cl_abap_unit_assert=>assert_equals(
+        exp = '03:35'
+        act = cut->get( ) ).
+
+  ENDMETHOD.
+
+  METHOD subtract_more_than_two_days.
+    cut = NEW zcl_clock( hours   = 2
+                         minutes = 20 ).
+
+    cut->sub( 3000 ).
+
+    cl_abap_unit_assert=>assert_equals(
+        exp = '00:20'
+        act = cut->get( ) ).
+  ENDMETHOD.
+
+  METHOD wrap_around_backwards.
+    cut = NEW zcl_clock( hours   = 0
+                         minutes = 30 ).
+
+    cut->sub( 60 ).
+
+    cl_abap_unit_assert=>assert_equals(
+        exp = '23:30'
+        act = cut->get( ) ).
+  ENDMETHOD.
+
+  METHOD wrap_around_day.
+    cut = NEW zcl_clock( hours   = 5
+                         minutes = 32 ).
+
+    cut->add( 25 * 60 ).
+
+    cl_abap_unit_assert=>assert_equals(
+        exp = '06:32'
+        act = cut->get( ) ).
+
+  ENDMETHOD.
+
+  METHOD wrap_around_day_backwards.
+    cut = NEW zcl_clock( hours   = 5
+                         minutes = 32 ).
+
+    cut->sub( 25 * 60 ).
+
+    cl_abap_unit_assert=>assert_equals(
+        exp = '04:32'
+        act = cut->get( ) ).
+  ENDMETHOD.
+
+  METHOD equivalent_clocks.
+    cl_abap_unit_assert=>assert_equals(
+        exp = NEW zcl_clock( hours   = 15
+                             minutes = 37 )->get( )
+        act = NEW zcl_clock( hours   = 15
+                             minutes = 37 )->get( ) ).
+  ENDMETHOD.
+
+  METHOD inequivalent_clocks.
+    cl_abap_unit_assert=>assert_differs(
+        exp = NEW zcl_clock( hours   = 1
+                             minutes = 1 )->get( )
+        act = NEW zcl_clock( hours   = 18
+                             minutes = 32 )->get( ) ).
+  ENDMETHOD.
+
+  METHOD equivalent_clocks_1.
+    cl_abap_unit_assert=>assert_equals(
+        exp = NEW zcl_clock( hours   = 3
+                             minutes = 11 )->get( )
+        act = NEW zcl_clock( hours   = 99
+                             minutes = 11 )->get( ) ).
+  ENDMETHOD.
+
+  METHOD equivalent_clocks_2.
+    cl_abap_unit_assert=>assert_equals(
+        exp = NEW zcl_clock( hours   = 22
+                             minutes = 40 )->get( )
+        act = NEW zcl_clock( hours   = -2
+                             minutes = 40 )->get( ) ).
+  ENDMETHOD.
+
+  METHOD equivalent_clocks_3.
+    cl_abap_unit_assert=>assert_equals(
+        exp = NEW zcl_clock( hours   = 17
+                             minutes = 3 )->get( )
+        act = NEW zcl_clock( hours   = -31
+                             minutes = 3 )->get( ) ).
+  ENDMETHOD.
+
+  METHOD equivalent_clocks_4.
+    cl_abap_unit_assert=>assert_equals(
+        exp = NEW zcl_clock( hours   = 2
+                             minutes = 2 )->get( )
+        act = NEW zcl_clock( hours   = 2
+                             minutes = 4322 )->get( ) ).
+  ENDMETHOD.
+
+  METHOD equivalent_clocks_5.
+    cl_abap_unit_assert=>assert_equals(
+        exp = NEW zcl_clock( hours   = 2
+                             minutes = 40 )->get( )
+        act = NEW zcl_clock( hours   = 3
+                             minutes = -20 )->get( ) ).
+  ENDMETHOD.
+
+  METHOD equivalent_clocks_6.
+    cl_abap_unit_assert=>assert_equals(
+        exp = NEW zcl_clock( hours   = 7
+                             minutes = 32 )->get( )
+        act = NEW zcl_clock( hours   = -12
+                             minutes = -268 )->get( ) ).
+  ENDMETHOD.
+
+  METHOD hours_rollover.
+    cl_abap_unit_assert=>assert_equals(
+        exp = '04:00'
+        act = NEW zcl_clock( 100 )->get( ) ).
+  ENDMETHOD.
+
+  METHOD minutes_rollover.
+    cl_abap_unit_assert=>assert_equals(
+        exp = '04:43'
+        act = NEW zcl_clock( hours   = 0
+                             minutes = 1723 )->get( ) ).
+  ENDMETHOD.
+
+  METHOD hours_and_minutes_rollover.
+    cl_abap_unit_assert=>assert_equals(
+        exp = '00:00'
+        act = NEW zcl_clock( hours   = 72
+                             minutes = 8640 )->get( ) ).
+  ENDMETHOD.
+
+  METHOD negative_hours_rollover.
+    cl_abap_unit_assert=>assert_equals(
+        exp = '05:00'
+        act = NEW zcl_clock( -91 )->get( ) ).
+  ENDMETHOD.
+
+  METHOD negative_minutes_rollover.
+    cl_abap_unit_assert=>assert_equals(
+        exp = '16:40'
+        act = NEW zcl_clock( hours   = 1
+                             minutes = -4820 )->get( ) ).
+  ENDMETHOD.
+
+  METHOD negative_hours_and_minutes.
+    cl_abap_unit_assert=>assert_equals(
+        exp = '22:10'
+        act = NEW zcl_clock( hours   = -121
+                             minutes = -5810 )->get( ) ).
+  ENDMETHOD.
+ENDCLASS.