I've been working on a Lego build for three years and four months.

I started when I got the Lego ninjago movie set 70615: the fire mech, and have been steadily improving. I was upset that the set didn't have knees like it did in the movies, so I decided that was unacceptable, and need to fix it. Firstly I used technic rotation joint bricks which could move in 360 degrees around and 180 degrees side to side and up and down, but they were to weak to hold up the weight of the lower leg, so I changed those for the newer technic rotation joint disk joint's which can only move in 180 degrees up and down, but that's all I need the knee to do and it can hold up the weight of the lower leg. I then added load more unnecessary details.

After fixing up the legs I stared work on the torso/cockpit. Ordinally the cockpit was designed for a minifigure to be able to fit in siting down, but I wanted the minifigure standing, so I had to dismantle almost the entire torso. I lengthened the cockpit, and I had to add a 4x6 plate to the back so it would fit and not look wonky. I also added three additional plates you had to open up to open the cockpit on top of the original clear cockpit piece the set used. I then made a mechanical looking 2x3x2 brick section that connects the cockpit back and waist to each other. After that like the legs I added a lot of unnecessary details.

After finishing the torso/cockpit I moved on to the arms. I entirely dismantled the arms the original set made only using the approximate length and width of them. I made one arm (the left one) entirely by myself with three sections: the first which connects to the torso, the second which acks a wrist, and a third which is the hand. For the hand's "fingers" I used two pieces that I got from the Bionicle's set of either 2016-17. For the other arm (the right) I had my brother help me since he is way better at making arms and organic looking and moving humanoid figures. This arm's section that attaches to the torso is what the other arm's equivalent section is based on. The hand is much simpler and has four finger's this time, it also uses 12 pieces in total. The middle section longer then the other arms and has a gun looking attachment as well. both arms have a lot of unnecessary detail on the as well.

TL;DR Was upset that a Lego mech set didn't have knees, so added them myself and kept improving the mech for three years and four months and am still working on and improving.

I'm still not done working on and improving my mech. The arms still use the technic rotation joints the legs used to, so they aren't really able to lift the weight of the arms. So I still have a lot to work on.