Antipode · Concentric · Shockwave

Rotates the great circle's plane around the point–antipode axis — the only free parameter for a circle through two fixed points.

Draws rings of constant angular distance from the selected point, spaced evenly in degrees.

Concentric wavefronts expanding from the origin. Rings that pass the antipode refocus there and re-expand, so fast/long-lived waves can lap the globe more than once.

Speeds the wave up as it converges toward the origin or focal point, and slows it down mid-path, modeled on documented antipodal seismic-wave amplification. Experimental — see chat for the research behind it.

Slows the wave over opaque (land) map regions; leaves it at full speed over transparent (sea) regions. Speed never recovers, so it can stall out entirely. Only the directions currently over land are held back, so the wavefront can become asymmetric over time. Requires an uploaded map.

Click the globe to drop pins in sequence — each new pin draws a geodesic leg back to the last one. Click an existing pin to select it.

Sea legs are drawn in blue; land legs in gold. Purely visual — no actual coastline routing.