You can use the grid-type mirror to teach yourself how to use the reflective-on-both-sides-with-just-a-hole mirror... The glass on the back of the grid-type mirror (Coghlan's model) is just reflective enough to view a dim reflection of your hand and the spot of sunlight that shines through the hole. Comparing the reflection with the location of the bright spot provided by the grid yielded an "aha" moment, at least for me.

BTW can anyone explain the optics that creates the bright spot in grid-type mirrors?

Thanks!
Steve
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"After I had solaced my mind with the comfortable part of my condition, I
began to look round me, to see what kind of place I was in, and what was
next to be done"