An interesting riddle


Refer to this picture.

It is a little figurine of a cardinal (tail-less, unfortunately, due to an accident) sitting on a feeding tray that doubles as a calendar. You notice the bar with the month names on the left, and you figure that there must be three of them, and you're right. You also notice the two visible dice-like cubes representing 13, March 13, today.

The riddle: how many cubes are necessary to represent any possible date? Four days ago, it would require two cubes showing 09.

You can see two day cubes; how many more are behind them?


I believe it can be done with just two cubes.

Each cube needs the digits 0, 1 and 2.
The remaining digits are spread over the rest of the faces and some rotational symmetry is taken advantage of.

- Pauli


I get the same answer. The dice could be as follows: 0:1:2:3:4:5 and 0:1:2:7:8:9.


Hold on! What happened to 6? Shouldn't a face of the second die be 6 instead of 0?

Edited: 13 Mar 2012, 10:19 p.m. after one or more responses were posted


Turn the 9 upside down to get the 6. You don't need a 3 on the other cube.

Edited: 13 Mar 2012, 10:20 p.m. after one or more responses were posted


Oops, silly me.


6 / 9. See Pauli's note about "rotational symmetry".

You have to have 0, 1, 2, on both cubes. 3 - 9 are only needed on one cube. 9 flipped is a 6.




Again, oops, silly me.


Katie beat me by seconds <g>. Only reason she got there first was that she typed less! She probably also types faster...



I sometimes type fast, but make a zillion typos when I do. That's why you often see my edits shortly after I post something.


LOL. I also seem to have that particular disease.




I also make it 2. Clever little riddle.


You people are sooooo good.

When I was eleven years old, my buddies and I thought it was so cool that the year on the US penny minted that year was the same if you looked at it upside-down.

When was I born? What is the next year that will be the same upside-down?



Or.... after reading the next post, 1950 and 6009! Patience Grasshopper.

Edited: 13 Mar 2012, 11:32 p.m.


1961 / 6009

Actually you asked when you were born -- that would be 1950.

Edited: 13 Mar 2012, 11:19 p.m.


Right, as usual.

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