If you want them, get them soon, before the Escher estate sends the Cease and Desist. I adore Escher related tat, but anything authorised is hugely expensive (the foam lizard tiles, which we have, work out at about £3 per tile, for example), and they're pretty rigorous about pursuing their copyright. Steven bought a shirt from Sainsbury's last year with the lizards on it; clearly not an authorised product.
Escher Pavers