Leaf: basal 1--25 cm, blade < 4 cm, < 3 × longer than wide, elliptic to reniform, tip rounded to acute, petiole linear; cauline fused into < 10 cm diam, round, +- obtuse-angled, or +- square disk (or free on 1 side).
In shape it is an obtuse-angled parallelogram, p21 about 100 yards wide, and the defence consists of two banks with a ditch between them.
Typically growing to 78 cm across, the bluntnose stingray is characterized by a rhomboid pectoral fin disc with broadly rounded outer corners and an obtuse-angled snout.
"I wanted something that would make a geometry from the play, a more right-angled geometry, in two ways," he said.
The building features the architect's angled geometry and uses metallics and coated glass, similar to the architecture across its plaza in Mr. Libeskind's Frederic C. Hamilton Building, an expansion of the Denver Art Museum.
This point represents a potential problem spot because presently available devices are unable to conform to such abruptly angled geometry, especially along the lesser curve, and/or a lack of fixation in this area can lead to a fatal disaster.
Riemann himself pointed out that, merely by calling the geodesics of a sphere "straight lines," the maligned hypothesis of the obtuse angle produces the geometry appropriate to the sphere's surface.
Since the hypothesis of the obtuse angle correctly characterizes Euclidean geometry applied to the surface of a sphere, the non-Euclidean geometry based on it must be exactly as consistent as Euclidean geometry.
If this is disallowed, the hypothesis of the obtuse angle produces a system equivalent to standard spherical geometry, the geometry of figures drawn on the surface of a sphere.
C. S. Lewis's armoire that opens into Narnia is a charming fancy, while Navidson's cave is an affront to our sense of space and direction, like those memorable geometries of H. P. Lovecraft, in which obtuse angles behave as if they were acute -- angles swallowing us down.
