The abutment is at right angles and therefore spoils the recurve.

An appendage at that point is considered to spoil the recurve or obstruction.

Placing the delta upon the recurve would spoil that recurve.

It must be free of any appendages abutting upon the outside of the recurve at a right angle.

These tented arches have two of the loop characteristics, recurve and delta, but lack the third, the ridge count.

There are also the elements of the type approaching a loop, as it has a delta and ridge count but lacks a recurve.

This pattern has a recurve and a separate delta, but it still lacks the ridge count necessary to make it a loop.

An appendage connected at that point is considered to spoil the recurve on that side.

The second recurve, however, need not be a continuation of—or even connected with—the first.

If no second recurve is present, an obstruction at right angles to the inner line of flow is acceptable in lieu of it.