Sim

To begin, draw 6 dots arranged in a hexagon shape. Players take turns drawing straight lines between any two dots that do not already have a line. Each player should use their own color.

The object of the game is to avoid completing a triangle made entirely of your own colored edges. Only triangles that use the original 6 dots as their points are considered. Tiny triangles that are created through interesting lines are ignored. The player who is forced to draw a triangle of their own color is the loser.

Example Sim game showing the starting position, a game in progress, and a final game where red has lost.

Strategy

The game will last, at most, 15 moves, and it can never end in a draw. A basic strategy is to draw your line in such a way as to minimize the number of lines of your color coming out of each dot. In other words, don't draw a second line out of a dot unless you have no other choice and don't draw a third line coming out of a dot unless you have no other choice.

A more advanced strategy is to start your next line where your previous line left off, and connect to the dot that you have visited the least often (assuming it doesn't make a triangle).