Basic math math

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[>>>] Generating Attributions log:

[0] Thing Title : home wind turbine
[0] Thing URL : http://www.thingiverse.com/thing:16626
[0] Thing Author : sinux
[0] Thing Licence : Creative Commons - Attribution - Share Alike

[1] Thing Title : MK7 Type Extruder - Heavy Duty
[1] Thing URL : http://www.thingiverse.com/thing:27284
[1] Thing Author : shmorgan
[1] Thing Licence : Creative Commons - Attribution - Share Alike

[2] Thing Ti