COBOL code

       identification division.
       program-id. game-main.

       data division.
       working-storage section.

       copy rl-keys.
       copy rl-bool.
       copy rl-def.

       01 is-closing pic 9 value 0.

       01 w-width pic 999 value 800 is external.
       01 w-height pic 999 value 600 is external.

       procedure division.

         call "SetTraceLogLevel" using
          by value rl-log-error end-call
         call "InitWindow" using
          by value 800 600
          by reference "Game" end-call

         perform until is-closing = rl-true

          call "WindowShouldClose" returning is-closing

          call "BeginDrawing"

          call "update"

          call "paint"

          call "EndDrawing"

         end-perform

         call "CloseWindow"

       .

       end program game-main.

       identification division.
       program-id. update.

       data division.
       working-storage section.

       procedure division.

       end program update.

       identification division.
       program-id. paint.

       data division.
       working-storage section.

       copy rl-keys.
       copy rl-bool.
       copy rl-def.

       procedure division.

       call "b_ClearBackground" using
        by value 245 245 245 255 end-call
       call "b_DrawRectangle" using
        by value 50 50 50 50
        255 0 0 255
       end-call.

       end program paint.