Walking on custard

aviva_m and I discovered the other day, whilst investigating whether custard is made with eggs or not^* that (unless we are the victim of a vast conspiracy covering Wikipedia and YouTube) it is possible to walk on custard, as it is a non-Newtonian liquid:

* livredor told me it was, but my Bird's Custard does not; this, it turns out, is because Alfred Bird's wife was allergic to eggs.