module spreizkonus( part, d, sd, mount=0, bottom=1) {
	assert( "bottom" == part || "top" == part, "First parameter (part) must be \"bottom\" or \"top\".");
	s = mount;
	b = bottom;
	h = d+s+b;
	c = 1 + sqrt( 2*h^2);
	m = "bottom" == part ? 180+45 : 45;
	v = "bottom" == part ? sd : 0;
	
	difference() {
		intersection() {
			translate( [0,0,s/2-b/2])
				cylinder( d=d, h=h, center=true);
			rotate( [0,m,0])
				translate( [0,0,c/2])
					cube( c, center=true);
		}
		translate( [0,0,s/2-b/2])
			hull() {
				cylinder( d=sd, h=h+1, center=true);
				translate( [v,0,0])
					cylinder( d=sd, h=h+1, center=true);
			}
	}
}


/*
spreizkonus( "bottom", d=30, sd=4, bottom=2);
translate([0,0,1])
	spreizkonus( "top", d=30, sd=4, mount=2);
*/