Note that different people have different research approaches. The two old ladies check that none of them can see herself and the problem is solved! ;-)
The other older lady makes an experiment with motion and rigorously determines that she is ... well ... unsichtbar. :-)
Will a Breakthrough Solar Technology See the Light of Day? - A startup that might have a record-breaking solar cell is in danger of going out of business. The power unit is a rectangular slab about the size of a mo...
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