Field guide No. 641
Cow grazing at the color boundary
Eating the colour as she goes.
A black and white cow grazes where a field turns from bright green with yellow flowers to plain grey, and the grey is behind her. She eats the colour as she goes.
Field noteCows eat grass. This one eats its colour too and leaves the field grey behind her, mowed to monochrome.
Also possible, also breaking physics
Avalanche against an invisible boundarySnow slides until it runs out of slope. This lot stops dead at a line nobody can see, sheared flat like a cut cake.
Inverted meteorite crater in white chalkWhite chalk surrounds a reversed crater. The meteorite was excavated from underneath.
Corridor zipped into itselfHallway walls meet at the far end along a zip, teeth and all.
A door for nobodyDoors don’t usually hold back streams while lying down. Water’s choice, not a contradiction.