has 180-degree rotational symmetry around a vertical axis. It has a second symmetry that comes from reflecting it across a horizontal plane while at the same time rotating it 90 degrees.

The line \(x = -1\) is a vertical line which passes through -1 on the \(x\)-axis. The line \(y = 1\) is a horizontal line which passes through 1 on the \(y\)-axis. The shape has been reflected in ...

If a hard-boiled egg is spun sufficiently rapidly on a table with its axis of symmetry horizontal, this axis will rise from the horizontal to the vertical. (A raw egg, by contrast, when similarly ...

His solution is the E2, a 21:9 device with a horizontal symmetry, and what he says is "a large screen, a relatively small size, no vertical orientation bias, and no compromises." Specs for his ...