i have a little puzzle for you folks

I am putting in a 450+ foot patio and i have 8) 2' squares where I will need a 4" corner to complete the pattern

we are using mostly the red 12x12x2" concrete tiles, a pattern that uses 8 squares of 16x16x2" with brick (4x8x2&quot borders.

finding a 4x4x2" paver with a color pop is seemingly impossible, so..... I want to use a frost proof Mexican or porcelain tile in those 32 4x4" spots.

how (or what) can i use to build up the 4 inch area where a standard floor tile will work? most tile is 1/4 inch or so. can i just use a bunch of the leveling sand? do i need to put a square of backer board on the tile (it's hopefully going to be a netted mosaic or maybe not..)

i will be finishing with poly sand to bond it all together.

this is the Chihuahuan dessert so it freezes in the winter and bakes in the summer.

suggestions?