The trouble is, now that the twins can sort of walk, the house is shrinking,"" reports the eldest child, whose nursery-school rabbits are regular weekend visitors that swell the ranks of the many resident pets: her home is bursting at the seams. A search turns up several unsuitable alternate houses--they are too big or too decrepit, or have mice or odd smells. The happy solution (as in Shirley Hughes's The Big Concrete Lorry, 1990) is a homemade addition. All this is recounted in amusingly realistic detail, nicely amplified in the author's sympathetic, charmingly comical illustrations.