Good contrast between floor and walls. This gives an immediate impression of the extent of the lift.
Mirror on the back wall

Brightly lit lift interior.
Mirror on the back wall.
Reasonable contrast between walls and floor.

Very poor contrast between wall and floors as they are all covered with the same carpet material.
The only differentiation is as a result of the different angles that the light falls on the surfaces.
No mirror on the back wall.

Good colour and tonal contrasts
but no mirror on the back wall.