The gold cubes must be completely surrounded by the red cubes, even when you lift the assembly off the table.
This popular puzzle was inspired by a partial hiding puzzle by
The pieces shown above are of my own manufacture.
The finish is Liquitex
soft-body acrylic in cadmium red,
producing a strikingly vivid effect.
Later I made a copy using Daler-Rowney's
in phthalo green.
The paint produced an unexpected streaked effect
that many find appealing.
Since then I have experimented with other paints. A version in exotic woods is available from Wood Wonders.