Leaning over to look past Glamerspear at the corporal, the colt smiled even more. "Just like an echo! But with light in this case, instead of sound. Anyways, the idea is that if you want to make someone believe there's a table in front of them, you don't have to actually make a table, you just have to make something that reflects light, echoes sound, and pushes back against pressure like a table would."