a Keith Richardson-Jones picture

this picture by Keith Richardson-Jones (1974) is in the Tate, London UK

there is an interesting structure to it, that seems not too difficult to discern

John Golden (@mathhombre) has produced an interactive, using Geogebra
it varies the inclinations of the lines
here

block graphs

who are these cartoon characters?

Jung Von Matt

lattice labyrinth tessellations

these very intricate designs are created by David Mitchell

a book on how to create such designs is available from Tarquin

David's blog is here

David draws attention to a pdf that outlines some theoretical, condensed aspects of this fascinating study (many thanks)

not David's designs, but in a similar (but far less complex) vein ...
copy and continue these tessellations:

Lee Westwood and Sama Mara

maybe you could play these videos to your students

a collaboration between a composer (Lee) and an artist and geometer (Sama): 
kaleidoscopic patterns, synchronised to a musical score

their work ('a hidden order') is to be found here

there is (static) art work as well as videos and other ways to explore generated patterns

several Vimeo videos explore their interpretation of the relationship between pattern and music including:

triangle ensemble
hexagon 1 ensemble
and, my favourite,
octagon 1 flute and marimba

thanks to J Mowl for bringing this to my attention

circular associations

from circular associations

the geometry of music

Pachelbel

Vivaldi
Bach

more Pachelbel,
different representation

pure geometry

'Pure Geometry' by Romanowsky
on Vimeo

Damien Hirst art

Damien Hirst's spot paintings are well known

how would you easily count the dots in these artworks?

Souzou

a 'Souzou' exhibition was held in 2013 at the Wellcome Collection in London
some of this exhibition could be viewed online

all the artists have received little or no tuition and produce work for the sake of creation alone, with no audience in mind

they have been diagnosed with a variety of different cognitive, behavioral or mental illnesses and attend or reside in specialist care institutions in Japan

Shota Katsube's figures are made from the twist-ties used to fasten bin liners:

Kenichi Yamazaki's drawings are like engineering schematics and are created in the confines of his hospital ward, using a compass, ordinary pens and large graph paper:

pencil art by Jennifer Maestre

Jennifer Maestre

Peter Monaghan

I think the work of this Dublin artist is just great...
his website
the home page can be viewed full screen
interaction on youtube