The basic rules are:
1.You can define any tile, even if one doesn't exist in the game yet.
2. All dimensions must be multiples of 5.
3. The longest side must be the x-axis (width). Having both sides the same is fine.
4. Do not use the characters: ' (apostrophe) or \ (backslash)
Here's an example:
--Three mostly empty shops
--Author: Lap
--30x15
defineTile('.', 'FLOOR_WOOD_ONE')
defineTile('S', 'SIDEWALK')
defineTile('P', 'PAVEMENT')
defineTile('B', 'WALL_BRICK_DARK')
defineTile('d', 'WALL_BRICK_DARK_DOOR_BACK')
defineTile('D', 'WALL_BRICK_DARK_DOOR')
defineTile('O', 'DOOR_WOOD_DOUBLE')
defineTile('c', 'COUNTER_WOOD_RED')
defineTile('C', 'CABINET_WOOD')
return {
[[SSSSSSSSSSSSSSPPSSSSSSSSSSSSSS]],
[[SBBBBBBBBBBBBBPPBBBBBBBBBBDBBS]],
[[SB...........BPPB.C.D.......BS]],
[[SB...........BPPB...B.......BS]],
[[SD...........BPPBBBBB.......BS]],
[[SB...........dPPPPPPd.......BS]],
[[SBBBBBBBBBBBBBBdBBPPB.......BS]],
[[SB...............BPPB.......BS]],
[[SB...............BPPB.......BS]],
[[SB.........ccccccBPPB.......BS]],
[[SB...............BPPB.......BS]],
[[SB...............BPPB.......BS]],
[[SB...............BPPB.......BS]],
[[SBBBBBBBOBBBBBBBBBPPBBBBBDBBBS]],
[[SSSSSSSSSSSSSSSSSSPPSSSSSSSSSS]]}
Remember that most of the time streets will be surronding all sides of your plot so making a 5x5 little house would look silly. Even having a single house surrounded on all sides kind of looks silly. If you want to make 3 separate houses you can make them and then paste them in different combinations into a larger plot. Maybe you make a few plots where all three are there in different positions with different surrondings or maybe you also make a couple that just have one or two houses.