#193 Flush tiling
Set by Alison Kiddle
Bonnie is refitting her bathroom and her plumber has brought round some very peculiar tiles to cover the floor. Her bathroom is a 5×5 square and each tile is an L shape made up of three squares (see the diagram above).
Bonnie has realised it will be impossible to tile the whole bathroom without cutting tiles, as each tile covers three squares and 25 isn’t a multiple of 3. When she points this out, however, her plumber says it is OK, as they will need to leave one square of floor space …