Nothing funny about feldspar

Next Week’s Challenge: Think of a familiar brand name ending in the letters G-S. Change the G-S to an O and you’ll get the brand name of a different product. What is it? Hint: The first word has five letters, and the second has four.

Hint: Brand 1 had an iconic plastic package, which has long since been changed out for cardboard. Brand 2 is familiar to anyone with children of A Certain Age (or those who were A Certain Age in the last 40 years).

Leggs –> Lego