This image of simple geometry is ineligible for copyright and therefore in the public domain, because it consists entirely of information that is common property and contains no original authorship.
This is a retouched picture, which means that it has been digitally altered from its original version. Modifications: convert to PNG, add grey border, change colour for different unit per: [1]. The original can be viewed here: 2-6 IC.jpg: . Modifications made by AustralianRupert.
Original upload log
This image is a derivative work of the following images: