08.24.08
Crazy map
I was checking out the Route for Notting Hill carnival tomorrow, and from the map – I’m none the wiser.
It looks like a metabolic pathway animation, but I suppose it scores 10/10 for UI WOW
08.04.08
Checksum
Here is a neat little trick to use when adding a tip to a bill to quickly detect possible foul play by the waiting staff. It only makes sense if you sign for the bill, not with chip and pin machines which are now very widespread.
http://www.punny.org/money/fight-thieving-restaurant-servers-with-checksum-tips/
The idea is that since you are in control of the tip, you can add a value to the final total in which the last digit of the cents column (or pence in normal currency) is used as a checksum for the dollar(or £) value.
I.e if a bill comes to £112.00, and you want to add a four pound tip. Then you add up the pound columns together with the tip to get 8 (1+1+2+4 = 8).
The final value for the bill is £116.08. Now if the waiting staff decided to ‘massage’ one of the 1’s into a 4 yielding a generous £146.08, then the checksum fails since (1+4+6) % 10 = 1, rather than 8.
Rumbled!
Note: that you can use modulo 10 (often written as %10) to ensure a single digit. I.e 1+4+6 = 11. If you divide by 10, then the remainder is 1 and so you write 1 as the checksum.
I often wondered why phone numbers haven’t made use of a checksum since it would cut down the number of wrong numbers.
Further reading:
- Detecting data entry errors in ISBN codes
- Benford’s law - detecting forged tax returns and expense forms