29 addresses, one for each kind of object a room record can place: bits 3 to 7 of a group byte in location_tbl, doubled, index this table (next_fg_obj). Each address points at a list of 6-byte parts ended by a 0 byte, laid out as described at block. Most kinds are one part; the two guards are two.

The table is not in address order: the records it points at are grouped by what they are (blocks, then fire and balls, then spikes and so on), while the index order is simply the order the kinds were numbered in.