Grids

Architectural subjects perhaps give the greatest sources of inspiration for the theme 'Grids', whether it be single buildings, as with David Hepher's photo realistic image above, or the cityscape as a whole, such as Vieira da Silva's intricate patterned interpretation below.
Tommy Cinquegrano's images at first glance look like one building, but on closer inspection you can see they are made up of multiple images taken from different sources, as in the image below. He relies on the common grid-like structures of the buildings to allow him to combine his photos so successfully.Seeing the geometric patterns within a scene is the source of inspiration for a diverse range of artists. William Gilles' almost naive view of a fishing harbour (below) evokes childhood memories.
Whilst Lyonel Feininger's work (below) takes on a Cubist sensibility in both tone and colour.The connection with George Braque's still life pieces is obvious, an example of which is below. Braque, along with Picasso, pioneered the Cubist movement.
David Hockney has long been fascinated with Cubism and much of his work reflects the theme of grids, whether it be his 'joiner' photographic work (as above), or his more recent depictions of the Yorkshire landscape and the patchwork patterns of the hedgerows and fields (below).
Jerry Gretzinger takes this idea further by using maps and aerial views as his main inspiration.
Another interesting interpretation of the photographic joiner, are French design practice PNTS's kaleidoscopic works (below), where the pattern element becomes the dominant factor.

Layers

'Layers' could be interpreted through the subject matter and/or the artist's method of working. Kurt Schwitters (above) created collages with found objects and then worked into them. Jacques Villegle was inspired by torn billboards (below) and particularly focused on the typographic elements.
Valerie Roybal is a contemporary artists working in collage, she takes books and journals and creates more orderly compositions, often incorporating embroidery (below). Just as Schwitters and Villegle, she juxtaposes images and text to allow the viewer to decide on their own interpretations.
Barbara Lee Smith is a textile artist who works in mixed media. Her landscape pieces are painted, printed and stitched. The work below is entitled 'Estuary' and you can see a detail below that.

Swedish illustrator Camilla Engman collects simple objects like these envelopes and then lets them inspire her narrative drawings.
Norma Starszakowna is a textile artist who uses mixed media techniques to create pieces that evoke the memories left within the walls of buildings.
Anthony Brown created a series of paintings for an exhibition in Liverpool about 100 famous creative people from the city. Each portrait is worked over the top of newspaper headlines, photographs and images of events from the subjects life, such as this portrayal of John Lennon.
Nick Gentry paints portraits on old floppy discs (see below), carefully aligning the pupils of the eyes with the centre of the discs.

Exotic

Henri Matisse was fascinated by the highly decorative textiles of North Africa, Eastern Europe and Asia. He would often use pieces from his own collection as backdrops or to dress his models.
Frida Kahlo (above) was proud of her Mexican heritage and would always depict herself in traditional costume. When bedridden because of illness she would paint the fruit,vegetables and birds of her native country (below).
Margaret Mee was a pioneering environmentalist. She spent many years travelling through the Amazon recording it's plant life with her beautiful illustrations (below)
Marc Quinn's highly coloured images of plants (below) exaggerate and emphasise their exotic beauty.

Alfresco

The classic images of people eating outside come from Impressionists such as Eduard Manet's 'Le dejeuner sur l'herbe' (above) and Auguste Renoir's 'Luncheon of the Boating Party' (below).
Vincent Van Gogh's 'Cafe de nuit' (below) is another famous depiction of alfresco eating, this time with more emphasis on the cityscape than on the people themselves.
Arthur Rackham's illustration for Alice in Wonderland (below) shows the Mad Hatter's tea party set amongst the trees.