It took me quite some testing to perfect this into a fabric and shape that will lie flat and have the right thickness. I settled for doubled yarn and slightly modified pattern.

I also made a matching small waste basket (cylinder shape, dc all the way).

Rug 2 & 3 (dark):
2x2 & 3x3 squares
Eco wool (about worsted weight) held double.
About 2x75 meters yarn (held double) makes one square.

Rug 4 & 5 (large, light):
3x4 & 3x3 squares, yarn held double
About 75 meters yarn (x2 - held double) makes one square.

Frogged (kept for reference)
Rug 1 (frogged):
3 x 3 squares upper side, lacy square pattern
3 x 3 squares backing, leaving out the lace

One layer of the lighter cotton yarn feels too skinny so I made a back side (eco wool, my production, about aran weight, doubled yarn, same hook).