Think about a digital clock using seven-segment displays. Clearly, the zero, the one, the two, the five and the eight read the same forward and back. The six and the nine interchange with each other when upside down and reversed. Three, four and seven do not reverse.
Given these properties, it can be seen that there are some times of day that read the same forward and upside down and backwards. For example, 1:01, 9:26, 5:25, etc. There are 720 separate times displayed on a 12-hour digital clock. Of those, 27 are palindromic. (Coincidentally, 72 and 27 are palindromes!).
I have been getting up in the mornings only on palindromic times. On golf days when I have to get up early, I will arise at 5:15 or 5:25. On more leisurely days, I might sleep till 8:28 or even 9:26. So hopefully the house will not catch fire at 3:00 AM. I will have to tough it out till 5:05 before I can get out of bed.
Life is a challenge when you are retired.
