MB puzzle from 1993, 529 double sides pieces, cut from both sides and the front and back are rotated 90 degrees. All black and white Dalmatians. It's called the 'worlds hardest puzzle'.
MB puzzels catalogus - LastDodo
Leuke puzzel konijn van MB (Art.15-2930) | Puzzels | Het Tierelantijntje
MB Spellen puzzels kopen? | Groot aanbod online | beslist.be