Matrices

• multiplication

  row x column (add)
• 1 0

  0 -1

  reflection in x-axis
• -1 0

  0 -1

  rotation of 180
• 0 1

  1 0

  reflection in y=x
• 0 1

  -1 0

  90 clockwise
• -1 0

  0 1

  reflection in y-axis
• 1 0

  0 1

  same