The assignment was make a kit with 2D elements which connect to make something 3D.

Here is an idea for a fire starter, consisting of a ring of three rectangles connected by tab and slot, with a slitted cut out acting as both louver and fuel.

A flame tornado forms when burning fuel drives a chimney which draws in air from the side, through louvers giving the air angular momentum some distance from the center. The spinning air feeds the fire in the center with a high angular velocity.

I decided to forgo the chamfered slot pair connection in favor of a tab and slot, a stronger if less elegant way of holding the elements together in a ring. The tab and slot construction was fast and robust. One prototype was thrown around the shop, and twisted to invert it several times, and still held fast.

I made an .svg file in Inkscape.  First, I drew the rectangle with tab and slot. Then an open ended rectangle, with cuts doubling until the fingers at the closed end of the louver are many and small.

The final version of the .svg file included color coding of lines to force the sequence of cuts. The software driver for the laser [model] included a “cut outline last” option, which was not sufficient ordering to allow for a clean cut. The option I used was “cut in order of colors,” which in this case was black, red, green, yellow, etc. The line color also held speed and intensity parameters; black, green, and yellow make the same full intensity cut, red at 6% of that to just cut the surface.

I made several iterations of the bifurcation pattern, which would be a good application for a design tool page. The relevant parameters are chimney diameter, bottom chamber height, and louver cut pattern.

Here is the fire starter ready to go, in a rusty charcoal chimney.

There are two symmetrical ways to make a ring of tab and slot rectangles, with the tab on the inside as shown, or the tab on the outside, which makes a more circular ring. In this case,  the triangular arrangement makes the ring hold in the chimney, without falling out when turned over.  I underestimated the size of the chimney by an inch.

 Loading the chimney with a layer of charcoal for test.

Just after lighting the center of the fire starter with a barbeque lighter.

I shot a quick movie of the fire starter in action.

The charcoal was well lighted by the structured cardboard.  After the fire starter finished burning, I moved the chimney to examine the ashes. The cardboard burns down to a fine white ash, and the charcoal is burning well.