This is a download of a mechanical model "Yes Indeedy". It is a cute sheep that nods "Yes" whenever you ask it a Yes/No question and turn the crank handle. http://www.robives.com/blog/asheep (still free I think!)
(There is a disagreeable sheep there too! http://www.robives.com/category/tags/sheep )
This one is quite simple to build. The design expects you to print double-sided on an ink-jet (unless of course you have a colour laser at home!). However, the solid blocks of colour on the reverse sides use a lot of ink, so you might like to just leave them white, or colour the reverse sides of the cut-out pieces some other way..
I used 200 grammes per square metre paper-board. No problem at all in my HP PSC1315 printer. 200gsm is about 0.65 ounces per square foot, best as I can work out. 80gsm is normal photocopy paper here in Australia.
No picture of mine at present, as I gave it to my daughter. She works in student support at a university, and perhaps the "Agreeable Sheep" can help them get their questions answered right away!
This page http://tardus.net/indeedy.html published: 11 Feb 2007