Submitted as a black pattern, I made it light and a few steps more subtle.
Source Andy
The starting point for this was drawn on the web site steamcoded.org/PolyskelionMaker.svg
Source Firkin
CC0 and a seamless pattern from a tile drawn in Paint.net .
Source SliverKnight
To get the tile this is based on, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
If you need a green background for your blog/website, try this one. Remember that Green Striped Background is seamlessly tileable.
Source V. Hartikainen
Seamless Prismatic Pythagorean Line Art Pattern No Background. A seamless pattern that includes the original tile (go to Objects / Pattern / Pattern To Objects in Inkscape's menu to extract it).
Source GDJ
I love cream! 50x50px and lovely in all the good ways.
Source Thomas Myrman
The square tile this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i
Source Firkin
Fabric-ish patterns are close to my heart. French Stucco to the rescue.
Source Christopher Buecheler
Prismatic Curved Diamond Pattern 3 No Background
Source GDJ
From a drawing in 'Prose and Verse ', William Linton, 1836.
Source Firkin
Prismatic Groovy Concentric Background 5
Source GDJ