First heard about it in a column in Scientific American by A. K. Dewdney. The rules are simple and it is rather fun. In one of his columns he talked about playing a toroidal version where a line going off one edge of a rectangular page comes back in on the opposite side.
• the board is first built by each player alternating in drawing an oval lightly (as with pencil) until 5 ovals are placed; each oval after the first must intersect another in at least one place, such as a tangent, but usually more
• every intersection gets a dot to emphasize its role as a vertex; the oval segments between them are edges
• after the board is built, one player starts by picking any vertex, and tracing (heavily or with a unique pen color) an edge from that point to a new vertex, and then to another vertex, and then to another (3 segments end-to-end per turn)
• the next player starts from the vertex where the previous player ended; if for any of their 3 segments (including the 1st) there is no legal move, their turn ends and the other player has choice of vertex to begin their next move
• if a player's move completes a loop, they capture it (adding their initials inside); first to capture 3 loops wins
So for example, the 5-rings olympic logo is a legal board (though one which allows the 1st player to immediately capture a 2-segment oval on either end).
Anyone else play this? Do I remember the name right?