April 14

• Warmup: 
• Homework: discuss oil/vinegar problem; moving candy into one place... 
• Three boxes: first has 6 less candies than 2nd and 3rd together; second has less candies than 1st and 3rd together. How many candies in the third box?
• Cop runs 3 times faster than a robber. Can cop spot the robber in a city of 4 square blocks (3 streets and 3 avenues)? 
• Periodic patterns: each 2x2 square on an infinite grid contain U D R C (unicorn, dragon, rabbit, cat). Is it true that each row or column contains all critters?
• Linear transformations: we know symmetries; what about shears?
  S:(x,y)->(x+y,y)Find images of a few points. Draw what happens to a cat.
• Do S^2. Find S^-1.