Acrylic paintings by Erik den Breejen, 2011-2014. From his Tumblr.
Paintings by Julio Le Parc, 1970-1974.
Tree of Life (1905) and Stoclet Frieze Knight (ca 1910) by Gustav Klimt.
Appearance Of Crosses by Ding Li
Continual painting series by Shanghai artist creates abstract colourful grids using the cross as his motif mark unit. He has been making these paintings for 20 years and is considered one of the most important abstract artists working in China today.
More can be discovered at ShangART Gallery website here
EDIT 2024: It seems like Ding Yi is the preferred romanization of the name.
Painted needlepoint canvases designed by Charley Harper. The original source is borked, but a more recent link is here. (Updated 2024)
Computer Graphics and Art, August 1976.
Cover by Waldemar Cordeiro. Peace & Love fabric design by Harjnder Rajasansi. Triangle painting by Roger Coqart. Mosaic by Groupe Couleur. George Washington portrait by C. T. Manning.
More at Triangulation blog (via nerdcore)
Chuck Close (b. 1940) used to be a photorealist painter and now works with mosaics. Seems to start working with a grid (often skewed) of background colours that he gradually fills with symbols.