[Sega]

Rashomon cannot be summoned from the air given that it is meant to emulate a gate. It emerges from the earth to act like a fence/wall that protects the user. Given that it's meant to emulate a kind monument, I believe a house formation is possible, but with four walls in a sort of pyramid like structure. This could be a single technique given that we've seen three and five rashomons made simultaneously with one jutsu.