gojo 1;

// A point gives place, without a grid or a world direction.
let $origin = point(carrier(), 0);
let $outward = orthogonal($origin);
root $origin;
root $outward;

// The unit promise is contour potential. Selecting a shared offset level
// supplies a path whose radial distance is still uncalibrated.
let $contour = crystal($outward);
let $offset_pattern = $outward -> (?reach -> $contour);
root $offset_pattern;

// Choose a radial segment and attach its ends. One tick here names the chosen
// radius; it is not one metre and does not create a circumference length.
let $ray = crystal(orthogonal($origin -> $origin));
let $radial_start = point($ray, 0);
let $radial_end = point($ray, 1);
let $radius = $radial_start -> $radial_end;
let $start = point($contour, 0);
let $radial = group($origin -> $radial_start, $radius, $radial_end -> $start);
root bind(?reach, $radius);

// One complete native traversal returns to the actual same starting site.
let $end = point($contour, 1);
let $whole = $start -> $end;
let $closure = $end -> $start;
let $circle_pattern = group($offset_pattern, $radial, $whole, $closure);
root $circle_pattern;

// Divide the whole. These are equal native contour parts, not X/Y samples.
let $fourths = carrier(subdivision(unit_of($contour), 4));
let $tenths = carrier(subdivision(unit_of($contour), 10));
let $degree_ticks = carrier(subdivision(unit_of($contour), 360));
let $fine_ticks = carrier(subdivision(unit_of($contour), 3600));
let $four = group($circle_pattern, span($fourths, 0, 4) -> $whole);
let $ten = group($circle_pattern, span($tenths, 0, 10) -> $whole);
let $degrees = group($circle_pattern, span($degree_ticks, 0, 360) -> $whole);
let $fine = group($circle_pattern, span($fine_ticks, 0, 3600) -> $whole);
root $four;
root $ten;
root $degrees;
root $fine;

// A landmark is selected on the constructed subdivision. The selected read
// attaches a new equal-reach radial segment and retains its derivation.
root group($four, point($fourths, 1));
root group($ten, point($tenths, 1));
root group($degrees, point($degree_ticks, 90));
root group($fine, point($fine_ticks, 900));
root group($fine, point($fine_ticks, 637));
root group($four, point($fourths, 4));
root group($four, point($fourths, -1));