Tetris Puzzle

A hard puzzle using 7 simple Tetris pieces, the goal is to put all pieces into the frame/box. It is surprising hard, and I haven't figured out the solution, but know that it is possible. I will post the solution later once I figured it out. I didn't design this puzzle, and the idea is from kid's contest, and I did the 3d modeling :)Boost Meboost if you like puzzles like this, more to come :)