BoAS] GEOMETRIC FORMS 319 
or angles of these zigzags which are filled in in color so that they 
appear to be triangles, are always termed beads in connection with 
the zigzag which is interpreted as the necklace. 
The ladder designs as evolved from combinations of triangles are 
of two general types. The one type is composed of single or double 
vertical or horizontal series of right-angled triangles (see sketches 
278-280; 287-296, p. 320); the other is the result of building right- 
angled triangles along an oblique line so that the hypothenuse of each 
268 
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AVAV 281 
279 
275 277 278 
figure is one with the line (see sketch 316, pl. 84). The former type of 
ladder was probably so called from its resemblance to the notched 
logs used for this purpose. No distinction is made if the whole 
design lies in a horizontal direction or is inverted. The right-angled 
triangle, whether single or in series, is also practically always called 
half-arrowhead. As a simple element it does not appear to be 
recognized as a triangle in itself, but always as half of a fuller figure, 
such as an isosceles or obtuse angled triangle. The single right- 
