Do this in master bath remodel. Use white subway tiles in the shower redo, build these niches and add these glass mosaic tiles to tie in the existing gray tile already being used (run it in the shower, the tub area and end in the commode area).
Walk-in shower corner for a spot to place a shower seat. Adding a white seat to the gray-tiled base lets the bench show up against walls gray-tile walls. The white seat also ties the bench to the mosaic-tile niches and river-rock-tile floor.