I thought horses just saw blue/green and grey and that they couldn’t see red/orange. So they saw stripes? Maybe they though it wasn’t flat (like those 3D flat painted crossings they have to slow down traffic). Poor horses.
Zebras should be black and white! There’s a road near us with funky artsy ones. One is very sensibly made up of words stencilled onto the road which aren’t easy to read (so the tourists slow don’t and peer at the ground as they cross the road - not dangerous at all!)