School holiday fun - card houses

week 2 of the school holiday and we're having an "at home" day today. In church yesterday Turtle busied himself building structures out of hymnbooks, and I thought that I would introduce him to card houses... The boys have been working hard at it for an hour now, trying to build 3 tiers. I am impressed with their patience and concentration. Every time their structures collapse, they start up again, tweaking the design slightly to make it more balanced and sturdy.