The can looked better. It was even more reflective than before. My brother-in-law Richard had set up a block of wood to help steady the tinder twig.  We took turns, and were able to get larger curls of smoke within 10 or 20 seconds of well-focused attention.

Sometimes we blew on the burning spot. It didn't burst into flames. We searched the yard for better tinder, trying leaves and grasses.

I should point out here that this was tougher than focusing light with magnifying glass. With a magnifying glass, you can see how the light is striking the target, you can see the shape of the concentrated sun and adjust your aim accordingly. With the parabola, the focal point was hanging in the air, and it was invisible unless your little twig was in the right place to catch it.

A tight bundle of very dry grass seemed like the perfect fire-starting tinder, but it posed a problem. The pinpoint of heat couldn't focus on a meshy bundle. I could see an eighth of the light energy on each of eight different strands, and when you are trying to harness a mere 2.5 watts of energy, that isn't enough to get a fire going.

We also tried a twist of newspaper. Newspaper was easier to focus the light on.

After about 45 more minutes, Grandpa Johnson came by and we gave up for the day.

No fire.

Maybe I needed to have polished the can more, or maybe I needed some practice making smoke into flames.

Maybe it was time to start looking around for a bigger parabola.