To sort chromosomes looking for trisomy.
A typical chromosome set like the one below. A complete set of chromosomes like this is called a chromosome spread or karyotype.
Print out the graphic below on a good quality printer, then cut out the chromosomes. To print it out, first click on the picture. When it opens in a new window, right-click the picture and click "Print". Now try to sort them into pairs by carefully looking at the patterns of banding on each chromosome and the lengths of the two arms on each chromosome. See if you can discover if this person has Down Syndrome or some other form of trisomy.