I am happy to release my primary calculator project for the last month or so, Invalid Tangram for the TI-83+/SE/84+/SE series. Invalid Tangram can best be described as a cross between Space Invaders and Tetris. Build block combos to gain powerups, then blast the enemies into oblivion while avoiding destruction. Instead of health, you have time: powerups add to your time, but enemy shots can remove it. Run out of time and the game ends. Invalid Tangram DE is based on the PC game by Josh Szepietowski and is available for both Doors CS 6.0 and Ion.