Routines| H | Number of character interested in the board |
| 26453 | 0603 | LD B,3 | Three blackboards on the top floors |
| 26455 | 1137D3 | LD DE,54071 | Point DE at the blackboard info table (see below) |
| 26458 | 2E02 | LD L,2 | |
| 26460 | 7E | LD A,(HL) | A=character's y-coordinate |
| 26461 | 2D | DEC L | |
| 26462 | B8 | CP B | Is the character on the top floor? |
| 26463 | 2807 | JR Z,26472 | Jump if so |
| 26465 | 1E3A | LD E,58 | |
| 26467 | 05 | DEC B | B=2 (two blackboards on the middle floor) |
| 26468 | FE0A | CP 10 | Is the character on the middle floor? |
| 26470 | 200C | JR NZ,26484 | Jump if not |
| 26472 | 1A | LD A,(DE) | A=x-coordinate of left end of a blackboard |
| 26473 | BE | CP (HL) | Is the character to the left of this blackboard? |
| 26474 | 3008 | JR NC,26484 | Jump if so |
| 26476 | C6n | ADD A,n | Is the character within n character spaces (n=4 usually, or 12 if coming from 28658) of the left of this blackboard? |
| 26478 | BE | CP (HL) | |
| 26479 | 3005 | JR NC,26486 | Jump if so |
| 26481 | 1C | INC E | Next blackboard |
| 26482 | 10F4 | DJNZ 26472 | |
| 26484 | 37 | SCF | Signal: character not standing at a blackboard |
| 26485 | C9 | RET | |
| 26486 | EB | EX DE,HL | Now HL points to the blackboard info table |
| 26487 | 7E | LD A,(HL) | A=x-coordinate of left end of blackboard |
| 26488 | 24 | INC H | |
| 26489 | 46 | LD B,(HL) | B=blackboard identifier (84, 90, 96, 102 or 108) |
| 26490 | 24 | INC H | |
| 26491 | 66 | LD H,(HL) | H=y-coordinate of top row of blackboard |
| 26492 | 6F | LD L,A | Pass the x-coordinate to L |
| 26493 | A7 | AND A | Clear carry flag to indicate success |
| 26494 | EB | EX DE,HL | |
| 26495 | C9 | RET |
| x | ID | y | ||
| D=211 | D=212 | D=213 | Room | |
| E=55 | 3 | 84 | 3 | Blue room |
| E=56 | 41 | 90 | 3 | Yellow room |
| E=57 | 161 | 96 | 3 | Top-floor room in girls' skool |
| E=58 | 32 | 102 | 9 | Science lab |
| E=59 | 161 | 108 | 9 | Middle-floor room in girls' skool |