Clay oven

http://www.engr.psu.edu/mtah/projects/clay_oven.htm

Snail top 

http://sustainablegarden.blogspot.co.nz/2009/10/wood-burning-pizza-oven-for-garden.html

Backyard clay oven, rubble st

Flick river

Portable

Unusual shape http://paleoplanet69529.yuku.com/topic/21309/Clay-Oven-on-Wheels#.UHC8R2thhP4

http://leojames.wordpress.com/2010/09/13/building-my-portable-clay-oven/

Indian pilgrim clay oven

http://www.flickr.com/photos/clodreno/464846102/

Igloo building

http://www.igloobuilding.org/

Clay heater

http://www.mha-net.org/docs/v8n2/wildac02.htm

Thumbprint http://aaronwymer.blogspot.co.nz/2010/09/nerd-alert-but-im-cool-with-that.html