Equations: sin(π sqrt((x + k sgn(y)/2)² + y²)) = 0

k = 1, 2, 3, ..., 8

Equations: cos(π sqrt((x + k sgn(y)/2)² + y²)) = 0

k = 1, 2, 3, ..., 8

Square Spirals (spirals made of half-squares):

Equations: sin(π(abs(x + k sgn(y)/2) + abs(y))) = 0

k = 1, 2, 3, 4

Equations: cos(π(abs(x + k sgn(y)/2) + abs(y))) = 0

k = 1, 2, 3, 4

Regular Polygon Spirals (spirals made of regular semi-polygons):

Equations: sin(π p(x + k sgn(y)/2, y)) = 0

k = 1, 2, 3, ..., 8

p(x,y) = sqrt(x² + y²) sec(π/n) cos(mod(arctan(y/x),2π/n) - π/n)

n = 6

Equations:cos(π p(x + k sgn(y)/2, y)) = 0

k = 1, 2, 3, ..., 8

p(x,y) = sqrt(x² + y²) sec(π/n) cos(mod(arctan(y/x),2π/n) - π/n)

n = 6

( Mathematical softwares used: Graph, gnuplot )