From the problem cellar
Four in a row problems
30 positions in three difficulties. A tick marks the ones you have solved in this browser.
Seven columns, gravity and one aim: four of your discs in a line before the opponent manages it.
Easy · #501–510
Win in two: your first disc should create two threats at once.
Medium · #511–520
Win in three: a forcing move first, then the double threat.
Hard · #521–530
Win in four: the threats have to be built in the right order so that every reply is forced.