### Times

Which times on a digital clock have a line of symmetry? Which look the same upside-down? You might like to try this investigation and find out!

### Transformation Tease

What are the coordinates of this shape after it has been transformed in the ways described? Compare these with the original coordinates. What do you notice about the numbers?

### L-ateral Thinking

Try this interactive strategy game for 2

# Penta Play

##### Stage: 2 Challenge Level:

These games were invented by Solomon W. Golomb, who came up with the idea of polyominoes.

Penta Play

For 2, 3 or 4 players

You will need:

• A chess board.
• Stiff card (preferably marked in squares)
• Scissors
• Paper
• Pencil and thin marker pen
• Ruler

Goal:

To be last person to be able to place a pentomino piece on the playing board.

To prevent your opponent(s) from finding space to place pentomino pieces on the board.

To prepare for play:

1. Find all of the 12 pentomino shapes*, sketch them on paper.
2. Draw them using the marker pen onto card that is marked in squares the same size as the chess board you use.
3. Don't mark the pentominoes in any way so that there is no way to tell the top, bottom, front or back.
4. Cut out the set of pentominoes.

To Play:

Version 1

• Divide the set of pentominoes between the players.
• Don't let other players see the pieces.
• Decide who will go first, second etc.
• Place a piece on the board to cover any five squares.
• The next player chooses a piece and places it onto the board.
• Try to block your opponents by leaving either no space for them to place a pentomino piece or a space into which their shapes won't fit.
• The winner is the last person to place a piece on the board.

Version 2

• Lay out all of the pentomino pieces.
• Decide who will go first, second etc.
• The first person chooses one of the pieces, then the second person chooses a piece etc.
• Players lay his or her chosen pieces in front of them for others to see.
• The first person to play chooses one piece and places it on the board.
• Players take turns to place pieces on the board.
• Try to decide which are the best moves to block opponents from placing their pieces.
• The winner is the last person to place a piece on the board.

Note:

The second version of the game requires players to use and develop their visual perception skills. Rather than rely on chance, as in the first game, players have to determine whether shapes held by their opponents will fill the spaces and which of their own pieces will alter the available spaces sufficiently to prevent play.

Computer Version (2 Players)

• Each player has 6 pieces. Player 1 has the first turn.
• Player 1 rotates pieces by clicking the button or flips them using the button. (Not all pieces have these. Why?) Take some time to learn how the pieces work.
• Player 1 then moves a piece onto the board.
• Players alternate turns.
• A player may click on the to find out if it is possible to move or not.

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