Are they the tiles that when you stand on them the liquid inside moves about? I've fixed a couple in a bathroom once, £150 a tile i think she paid, 500x500. Cant fix them with tile adhesive, you have to get a two part glue/resin which sets hard as nails, i think it was mapei adesilex g19 (not sure for defo though). It was two in a bathroom floor, we set it out so there was one you stood on when at the sink and one at the toilet. I thought it looked rubbish but thats just my opinion. I did have a picture but deleted when my phone photo memory was full. I also didn't grout around the joints of those tiles, just used the matching Silicon incase the grout cracked due to movement.