This is my take on the iconic Question Mark Box from the Super Mario Bros franchise. I'm sure there's no shortage of models for this, but I took it on as a challenge to quickly build this from scratch. And in that effort, I'd say I somewhat succeeded.

I provided a one piece file for those that can print multiple filaments and a set of files for those who can print only one filament at a time. Pictured is the question mark and bolts printed separately from the box. The clearance is tight (perhaps too tight), but it appears to fit snug and stays without glue.

You could print with 15% infill I'm sure, but that'd be a lot of wasted filament, unless you wanted a paperweight with some, well, weight. I printed mine with the lightning infill (quickly becoming my favorite infill pattern), and I feel it did a great job. Still, it took about 8h36m to print the box itself. I believe it would take about 2 days to print with 15% infill, so I wouldn't recommend unless you really need it.

Anyways, please post pictures and offer suggestions!