(a + i b + j c + k d)+(e + i f + j g + k h) = (a+e) + i ( b+f) + j ( c+g) + k ( d+h) a*e – b*f – c*g – d*h + i (b*e + a*f + c*h- d*g) + j (a*g – b*h+ c*e + … Continue reading devNotes 12-01-2016 Phi – Easel