This was the August, 1988 cover for Solid Waste & Power magazine. That really was its name! It served the growing industry of burning municipal trash to generate electricity. This cover was a variation on the puzzle idea; this one shows workmen directing the construction of a power plant made of toy wooden blocks. I've always suspected that construction workers recognize their line of work very early on – probably around three or four years of age – and their enthusiasm for building things never really goes away.