I don’t think so...then again i cant stand people making plans and then abandoning them. Then again, I suppose it depends on the reason why the reschedule. If they have a good reason (that doesn’t involve being lazy or doing stuff with other friends (unless they had plans first)) then I suppose it would be a little harsh, but other then that,
Tessellation's definition is identical shapes which fit each other and leave no gaps in between. For example you could have a tessellation of triangles or a tessellation of squares or even hexagons.