the boxes so as not to present any unsightly appearance on the outside for example as may be seen from fig2 and 4 the engagement means may be a rigid liner 24 upstanding from an inner surface of a lower box 12 to project into and position an upper box 12 immediately above it as shown liners 24 extend fully along both long walls 26 of the box 12 the liner 24 may only extend over one pair of opposed walls as shown alternatively the liner 24 may extend over long side walls 26 and over short end walls 28 alternatively a series of positioning pegs may extend upwardly from the inner surface of a lower box to position an upper box upon it the liners 24 may conveniently comprise elongate boards to rest on ledges 30 projecting inwardly from inner surfaces of long walls 26 the liners fit loosely against the inner surfaces of long walls 26 and may be prevented from tipping inwardly by rectangular spacer plates 32 extending across each box 12 between the liners 24 each spacer plate 32 of the lowermost box 12 rests on the top edge of neck 20 of foot 16 each spacer plate.