Rosie's guide to bridge building.

First, get the nice man to set up the former, around which the bridge will be built.

Next, put the blocks in at either end. Get someone else to do the end that you're not doing.

Keep adding blocks from the outsides in. The last piece you put in is called the key stone, right at the top.

Get the nice man to check all the block are in right, and then remove the former.

The bridge stays up on its own!!! (I'm not actually holding it up here).

To prove it, everyone has to walk over the bridge, but it's a bit too low to crawl under too. I walked on the bridge, but Mummy can't hold on to me and take a photo at the same time.