- The arches are sometimes
**cusped**; circles with trefoils, quatrefoils, &c., are introduced into the tracery, and large rose windows in the transept or nave, as at Lincoln (1220). - The polar form is {(u+p) cos 26} a+{(u-p) sin 20) a = (2k)t, where p and k are the reciprocals of c and a, and u the reciprocal of the radius vector of any point on the caustic. When c =a or = oo the curve reduces to the cardioid or the two
**cusped**epicycloid previously discussed. - The epicycloid shown is termed the "three-
**cusped**epicycloid" or the "epicycloid of Cremona." - If the ratio of the radii be as I to 4, we obtain the four-
**cusped**hypocycloid, which has the simple cartesian equation x 2'3+ y 213 = a 21 '. - Among the finest examples of this sort of work are the screens round the tombs of the Scala family at Verona, 1 35 0 - 1 375, - a sort of network of light
**cusped**quatrefoils, each filled up with a small ladder (scala) in allusion to the name of the family.

» more...

Create and save customized word lists. Sign up today and start improving your vocabulary!