These measuring sticks snap together to make different length measures.  Any two snapped together will reflect an accurate measure by adding the printed numbers on either side of the assembly.  You can use these to measure even inches from 3 to 13 inches.  

You could measure 1 or two inches too since they are one inch wide and the 1-2 on its own is 2 inches, which is easy enough but then the number adding doesn't work.  If you combine four pieces you would have to subtract 1 inch from the total, six pieces would subtract 2 inches and so on.  Following that scheme you could theoretically measure infinitely long with some thought.

I made these using Solidworks.