4 pieces of scenery and 15 objects in 4 groups. Positions are cells (U, V, level): U and V 0-7, sixteen units a cell from 72; each level twelve units up from the floor.

The room directory: 139 records, one per room, end to end up to SCENERY_TABLE. BUILD_ROOM finds a room by stepping from one record to the next until the number matches.

A record is +0 the room number, +1 the count of bytes that follow it, +2 the room's ink (bits 0-2; the builder adds BRIGHT) and its size (bits 3-7, an index into ROOM_SIZES). Then the scenery, two bytes an entry -- a scenery template (SCENERY_TABLE) and, for a doorway, the room it leads to -- up to an $FF; then the objects in groups, a header byte (bits 0-2: how many, less one; bits 3-7: the object template, OBJECT_TABLE) and a position byte for each: U in bits 0-2, V in bits 3-5, the level in bits 6-7. Nothing ends a record but the count at +1 running out, and a group can be cut short by it.

Each room is an entry of its own, laid out from the game's data when the disassembly is built.