One of the many tasks we got was to make "a box with a lid" and i interpeted that as a pocket flask since i prefer to make thing that could be useful.
You need brass, lead-free tin, a 3/8" lid, a 3/8" sleeve, some paper, sheet metal cutter and soldering torch. The lid are the same kind thats used on radiators and plumming, easy to find and usually cheap.
Step 1: The Template
Step 2: Cut the Metal
Polish the edges of the straight piece. In the next step it should be solderd.
Step 3: Soldering
If you use tin solder here it will part when you attaches the top and bottom.
When the soldering is ready you have to clean it. I used a light acid bath to cleance the metal.
Step 4: Tinning
Step 5: Assembly
Cut of the unnecessary brass with a metal scissor. Ground the edges to the right shape.
If you tin the outside you might get a nice effect by not soldering the ground areas.
Step 6: Polish
Use it with care, alcohol is not healthy, it's illegal to carry it in some places and times.