During some repositioning of gardentiles this rather large caterpillar suddenly appeared on top the sand underneath the tile, the Setaceous Hebrew character (Xestia c-nigrum) .
Probably the caterpillar didn’t sit under the tile but was ejected from one of the small plants in the tile seams. At first it was still curled up and I suspect it was still in winter rest. But after being exposed for some time it became active and started roaming. After the photo session I’ve put it elsewehere in fallen leaves.
References1 Vlinderstichting.nl, "Vlinders", De Vlinderstichting