September 30, 2016

La Jolla Shore


La Jolla, California, 2016.

Photo by I. Peterson

September 29, 2016

Tidal Swings


Tide gauges. Brannan Street Wharf, San Francisco, California, 2016.


The columns nestled within the red tubes rise and fall with the tide. Counting the stripes gives the height of the tide in feet.

See also "Tide Cycles."

Photos by I. Peterson

September 28, 2016

Tilted Donut


Tilted Donut 5 by Fletcher Benton. Corner of El Camino Real and Page Mill Road, Palo Alto, California, 2016.



Photos by I. Peterson

September 27, 2016

Airport Helical Toroid


A helix wrapped into a torus (ceiling detail). Concourse B, Denver International Airport, Denver, Colorado, 2016.


Photos by I. Peterson

September 26, 2016

September 25, 2016

Tiled Pentagons


Roof, Campbell United Methodist Church. Campbell, California, 2016.

For more pentagonal tilings, see "Tiling with Pentagons," "Pentagons for Floors," and "Splitting a Hexagon."

Photo by I. Peterson

September 24, 2016

Circuit Egg


Digital DNA by Adriana Varella and Nilton Maltz. Lytton Plaza, Palo Alto, California, 2016.


Photos by I. Peterson

September 23, 2016

Reuleaux Triangle on the Street


Reuleaux triangle. Third Street, San Francisco, California, 2016.

For more about Reuleaux triangles, see "Manhole Cover Geometry," "Drilling a Square Hole," and "Geometreks in Boston."

Photo by I. Peterson

September 22, 2016

Waterfront Arrow


Cupid's Span by Claes Oldenburg and Coosje van Bruggen. Embarcadero, San Francisco, California, 2016.

Photo by I. Peterson

September 21, 2016

September 20, 2016

September 19, 2016

September 18, 2016

Squares and Stripes




"A wall divided vertically into four equal squares separated and bordered by black bands. Within each square, bands in one of four directions, each with color ink washes superimposed."


Photos by I. Peterson

September 17, 2016

September 16, 2016

Mirror Bean


Cloud Gate by Anish Kapoor. Millennium Park, Chicago, 2010.

See also "Cloud Gate."

Photo by I. Peterson

September 15, 2016

September 14, 2016

September 12, 2016

September 11, 2016

September 10, 2016

Barn Studio


Mathematician and sculptor Helaman Ferguson transformed a barn dating back more than 150 years into a spacious though somewhat drafty sculpture studio. Bowie, Maryland, 1999.


Photos by I. Peterson

September 4, 2016

Main Channel Bridge


The cantilevered Main Channel Bridge spans the Mississippi River, linking Winona, Minnesota, and Latsch Island. Winona, Minnesota, 2008.


Photos by I. Peterson

September 3, 2016

September 2, 2016

Black Eyes


Rudbeckia. The Botanical Gardens at Asheville, Asheville, North Carolina, 2016.

Photo by I. Peterson

September 1, 2016