Chinitsu wait training. "Create Hand" generates a totally random set of tiles of 1 suit, and you should try to guess the hand state (won hand/和了, tenpai/聴牌, or 1+ shanten/向聴), and if the hand is not won, the optimal discard and the waits.
Size:
Images taken from https://github.com/FluffyStuff/riichi-mahjong-tiles with permission under the CC attribution lisence.