Mentalis (1977)

Mentalis, is a tile-laying game where players attempt to score points by completing squares of their colour.

The tiles, however, are reversible, and only the top side is seen by the opponent when initially placed. Once down a tile may be flipped by either player, but flipping a tile may reverse its colour, spring a trap, or present new movement and capturing opportunities.

Components are 50 double-sided tiles:
10 red/green
5 red/red
5 green/green
5 red/blue
5 green/blue
5 red/yellow
5 green/yellow
5 red/black
5 green/black
One board, one set of rules, two tile racks.