Raymond Unwin hypothetical (?)

This image is captioned 'Groups of buildings designed to maintain square roof lines on a curving road' on p. 346 of Raymond Unwin's Town Planning in Practice (1909). Although it appears in a general discussion of Letchworth Garden City it is not designated as an actual place and I suspect it may be hypothetical. Note the Tennis Court on the lower right and the small park on the top left featuring a sun dial.