Plaster model of the surface 2xyz=x squared -y squared-z squared +1=0 according to Prof Allardice circa 1891
Mathematical model of a geometrical surface with two apices, whose equation, referred to a suitable system of co-ordinates, may be written (x-p/a1)2 = 1/k6(c-y)3 (c+y), where p=1/f (c-y0 (c+y), q=1/g3(c-y)(c+y) and a,b,c,f,g & k are all constants. Mathematical model of a surface with two apices
Four plaster mathematical models of surfaces whose horizontal sections exhibit double points Four plaster mathematical models of surfaces whose horizontal sections exhibit double points
Set of two plaster mathematical models of surfaces showing projections of their sections onto a horizontal plane Set of two plaster mathematical models of surfaces