Nice work on fixing the chair, I completely agree with everything @pitrek121 said, the only thing I would add is that if you want the chair to have three legs (instead of 4, or any even number) it gets a little trickier to get the angle of the legs right, and I think the leg on the left should be angled further up, about half way from where it is to the top-left corner. With 3 legs there should be 120 degrees between each of them, so if you imagine (or draw) a circle around the bottom square you can divide that into thirds and that will show where each leg would land, but again, it's kind of tricky, and most of the time you can get away with kind of just eye-balling it, but right now it looks like the left and bottom legs are 90 degrees apart, and they both have 135 degrees between them and the right leg. It would also help to keep the same line weight as the rest of the line where the left and right leg meet the center because we shouldn't be able to see where they connect (like the middle leg).
But like Pitrek said, I must commend you for taking on such an ambitious design on the first project, keep up the great work!
