Copyright (c) 1970 Alexander Randolph - Stancraft Products
Dozo is a game played on a 7-side equilateral triangle board (with 28 cells) and with 4 sets of 7 stones of the same colors (a total of 28 stones).
The next player can win by dropping a green stone at cell  or a blue stone into cell .
The next player wins by dropping a red stone at , making a equilateral red triangle.
There is, at least, another way of winning? (select the next text to find the answer: drop a yellow stone at the bottom right corner
It seems unlikely the game ending without a player making a winning triangle but I do not know an argument (if any exists) that proves it.