Congratulations on getting through the challenge! I think this is normally the point where I'm legally required to ask you if you're feeling okay, and if you need help.

As a whole, I can see that you've had a good deal of fun with this challenge, and you definitely explored a lot of different interpretations of chests, as well as a wide variety of themes for your detailing. The constructions themselves ar eall looking great, so I'm going to focus in on your design choices, as well as a few little hiccups in how you approached some of the quirkier aspects of your drawings.

One thing that jumped out at me was with the octopus in the chest in #63. I think the addition of the octopus was a lovely touch, although there's one main issue with the octopus itself - its tentacles don't always feel entirely solid. There's been too much of a willingness to allow those tentacles to get squeezed really tight, or to actually flatten out. Basically their sense of volume wasn't always upheld. As shown here, ensuring that you're always thinking about how forms that are solid can reinforce that illusion is pretty important.

Another more minor point comes down to consistency when you're using areas of solid black. Every drawing we produce is an illusion, and the best way to maintain those illusions is to be consistent in the use of the tools we have at our disposal. Filling in the hole in the left side of the lid with black is a useful tool, effectively using that solid black to demonstrated a deeply shadowed interior - but as soon as we fail to hold to that rule we've established, we start imposing contradictions. If the inside of the lid isn't as heavily shadowed as that limited part suggests, then the viewer's brain must assume that it wasn't shadow. It must have been something else, but it's not clear what else it could be, leading to confusion and overall congitive stress. Your job is to lead your viewer by the hand to easily understand what they're looking at, so you want to avoid that kind of confusion.

Scrolling through many of your other designs, I can definitely see that you're trying to figure out what to incorporate into them to really push their believability, and you're definitely making some progress. I have some advice that should help, however.

Design is all about asking questions, and answering them. There's a lot we take for granted with the objects around us - we're not used to asking ourselves simple things like "how in the hell do those boards stick together to create the sides of that box?" We take it for granted that they're going to stick together, but as a designer it is your job to first ask yourself those questions, and then answer them within the design.

In cases like 52, I can see you playing around with rivets a bit - that's definitely good. But in a lot of these chests, there's no clear way in which the boards are secured to the overall frame. I also don't see much in the way of hinges to help the boxes open and close. These aren't things that the viewer will inherently pay attention to, but it's that sort of thing we assume to be present, even subconsciously. So leaving them out will be off-putting to some viewers. And of course, more importantly, asking ourselves these kinds of questions just gives us fodder to throw at our designs.

These kinds of everyday, boring features also give us a way to think about the scale of the object we're looking at. Whether it's a little chest or a space ship, generally speaking the ones putting them together still have human-sized hands, and human-sized tools. So the rivets and bolts will continue to sit in the same range of sizes. Of course you could have a race of giants, or maybe giant behemoth space ships are being built with big robot mechanics, but our job is to cater to the assumptions the viewer will make. So even in that case, the viewer's still going to interpret rivets and bolts as being of a size they can relate to. And to take that just a little bit further (on the space ship track), windows exist to be looked through by humans - so they're generally going to be human-sized too, except in certain special circumstances.

The last thing I want to talk about is wear and tear. Considering the history of the object you're designing will help you determine whether it should be in a pristine, untouched condition, or whether it needs to be scuffed, dented, scratched, and so on. Even a few scratches here and there can take a design from feeling like a concept or idea, to something real and tangible.

So! Hopefully I've given you some things to work with as you move forwards. Keep up the fantastic work, and consider this challenge complete.