Wallpaper group p2gg (pgg)

Tonight's wallpaper group is p2gg.

Key

	a centre of rotation of order two (180°).
	an axis of reflection.
	an axis of glide reflection.

 Image and Key: Source: Wikipedia

This cell has a more complex structure than before. The subunit is a half-rhombus. I begin with a rectangle and section it up:

Now clean up the lines a bit:

 I'm feeling like drawing this fire-breathing cat tonight.

 Now for the first glide reflection. I reflect over the axis that cuts through the ears, then slide the image to the right.

Now do the same with another cat, and slide it left.

 To get the next step, I rotated the top part 180 degrees.

Here it is without guidelines:

And here is the tiled repeat: