Here's the toy mat I made yesterday. It's about a metre square, which is hemmed around the edges. Then I made for handles (Rectangular piece folded in half length ways, then stitched to make a tube inside out. Turn the right way then close the end.) and stitched them on the four corners...easy peasy. Now they can tip their lego in the middle of the cloth and when they've finished then can pick it up with the handles and tip it all back into the box. Wonder if they will actually do it ;-).