create additional rows containing data from one original row
 

I have a spreadsheet of informational data containing mostly text that has
for each row one master id number, and then columns containing detail
information. one column for various colors, a second column for various
sizes.

I want to create multiple rows for each combination of master id number,
color, and size.

I figured a pivot table would be the best way to approach this, but I am not
certain where to start.