2008 July The Speed of Spiders   August Build A Cube     April Magic Squares   May Getting There And Back   June On A Collision Course January Square Numbers   February Number Series   March Happy Birthday   2007 October Toothpick Puzzles   November More Toothpick Puzzles   December Painting Cubes July Nets for Polyhedra   August How Many License Plates?   September How Much to Pack? April Magic Squares   May Magic Stars   June Boxes, Cubes and Nets January The Great Soccer Ball Giveaway   February Power to the Pedal!   March All the People in the World 2006 October Polyominoes   November Polyomino Puzzles   December How Fast Are You Moving? July Painting Cubes   August Let’s Shake on That!   September Hours Minutes and Seconds April Which Letter Is This?   May Seats at the Table or"No Function Too Large"   June Building With Bricks January Is It A Sale?   February How Can This Field Be Evenly Divided?   March The Tortoise and the Hare…Revisited 2005 October Four Square Matchsticks   November How Many Stamps Do You Need?   December Find the Heavy Ball July Are All Digits Equal?   August More About Benford's Law…   September Three Cubes April Telling Time   May The Commuter’s Choice   June Land and Water January The Reward   February Balancing the Books   March How Many Balls Are In The Bag? 2004 October Can 2=1?   November Around the World   December How Thick Does it Get? July What's Wrong with this Picture?   August What Are Your Chances?   September Different Dice April Rearrange the Coins   May More Trees in a Row   June Can You Build a Wall Around France? January Is it Straight?   February The FedEx Problem   March A Gallon of Water 2003 October How Many Regular Mosaics Can You Make?   November A Bargain Hotel?   December Matching Socks? July What Color Hat?   August Trees In A Row   September Which Bike is Free? April Telling Time with Burning Fuses   May A Tennis Ball Container   June How Can This Be True? January The Four Color Theorem   February Asking for Directions   March The Lines Problem 2002 October The Right Amount of Water   November Measure Exactly 8 Liters of Water   December To Tell the Truth July How Long Is The Coast Of England?   August Which Coin is Fake?   September Make it True April Float And Sink   May The Seven Bridges Of Königsberg   June The Monty Hall Problem January Number The Doors   February Where Are You?   March Dividing the Estate 2001 October Stringing Beads   November Connected Loops   December Bottleneck         September Fruit Juice Tasting