So it's not slippery. But crawling is done on any surface anyway. I have used it for years and it will certainly find its range of use until at least +/- 4/5 years of age.

Yes, that was the case with me. But this bag was never used again. Permanent use of the mat ;)

In reality, the colours are in between... On the first photo, the rendering is too dull, and on the second, it is too saturated...

There are 36 pieces and each piece is 30x30 cm :)

We assume that you are referring to the article at the link below: Puzzle mat 36-piece (180cm, 180cm) We are happy to confirm that the mats are compatible with each other.

Don't need to wash each time. I have wiped off minor spills using a damp cloth and mild detergent. If it were really bad, one could wash in the bath/shower and use e.g. Hand steriliser afterwards.