Candleplay is a Swedish table top mobile, powered by the heat of a single candle. This was bought in 1989 from the designer Harry Böstrom.
The mobile is delicately balanced on a metal point, so when the hot air from the candle rises, and hits the inclined metal disc, this causes the mobile to slowly rotate.
Harry describes it as a 'space age northern light in motion'.
The other mobile comes from Denmark, and was also bought in 1989. Called Aeromobile Crystal, it was designed by Börling Frederiksen.
Warm air rising through the tube will cause the two propellers to rotate in opposite directions.