Routines| A | Initial border colour |
| B | Delay timer |
| C | Next border colour (XOR) |
| D | Delay timer |
| 29836 | E5 | PUSH HL | |
| 29837 | 68 | LD L,B | |
| 29838 | D3FE | OUT (254),A | |
| 29840 | A9 | XOR C | |
| 29841 | 45 | LD B,L | |
| 29842 | 10FE | DJNZ 29842 | |
| 29844 | 1D | DEC E | |
| 29845 | 20F7 | JR NZ,29838 | |
| 29847 | 15 | DEC D | |
| 29848 | 20F4 | JR NZ,29838 | |
| 29850 | 3E01 | LD A,1 | BORDER 1 before leaving |
| 29852 | D3FE | OUT (254),A | |
| 29854 | E1 | POP HL | |
| 29855 | C9 | RET |