diff --git a/600_CELL_MAPPING.md b/600_CELL_MAPPING.md
index 3709453..70f9cc1 100644
--- a/600_CELL_MAPPING.md
+++ b/600_CELL_MAPPING.md
@@ -59,3 +59,29 @@ Arctic circle:
 555: 43
 393: 47
 
+Next: for each face on this icosahedron, find the other vertex - these are the next 20
+
+367
+131
+499
+179
+471
+165
+449
+258
+274
+95
+347
+313
+185
+140
+527
+573
+105
+585
+306
+207
+
+
+
+Then - for
diff --git a/label_inscribed_600cell.js b/label_inscribed_600cell.js
new file mode 100644
index 0000000..e0def94
--- /dev/null
+++ b/label_inscribed_600cell.js
@@ -0,0 +1,186 @@
+
+import * as POLYTOPES from './polytopes.js';
+
+import * as CELLINDEX from './cellindex.js';
+
+// script to help me label the vertices of one of the inscribed 600-cells of a 120-cell
+// with Schoute's partition (which is used to label the main 600-cell)
+
+
+function choice(a) {
+    const r = Math.floor(Math.random() * a.length);
+    return a[r];
+}
+
+export function nodes_links(links, nodeid) {
+    return links.filter((l) => l.source === nodeid || l.target === nodeid);
+}
+
+
+export function linked(links, n1, n2) {
+    const ls = nodes_links(nodes_links(links, n1), n2);
+    if( ls.length ) {
+        return ls[0]
+    } else {
+        return false;
+    }
+}
+
+
+export function dist(n1, n2) {
+    return Math.sqrt((n1.x - n2.x) ** 2 + (n1.y - n2.y) ** 2 + (n1.z - n2.z) ** 2 + (n1.w - n2.w) ** 2);
+}
+
+
+function round_dist(raw) {
+    return Math.floor(raw * 1000) / 1000;
+}
+
+export function make_one_600cell() {
+    const nodes = POLYTOPES.make_120cell_vertices();
+    const links = POLYTOPES.auto_detect_edges(nodes, 4);
+    for( const cstr in CELLINDEX.INDEX120 ) {
+    	POLYTOPES.label_nodes(nodes, CELLINDEX.INDEX120[cstr], Number(cstr));
+    }
+
+    links.map((l) => l.label = 0);
+
+    const nodes600 = nodes.filter((n) => n.label === 1);
+    const links600 = POLYTOPES.auto_detect_edges(nodes600, 12);
+    links600.map((l) => l.label = 1);
+
+
+    return {
+    	nodes: nodes600,
+    	links: links600
+    }
+}
+
+
+export function base_600cell() {
+        const nodes  = POLYTOPES.make_600cell_vertices();
+	const links = POLYTOPES.auto_detect_edges(nodes, 12);
+
+	links.map((l) => l.label = 0);
+
+	for( const p of [1, 2, 3, 4, 5]) {
+		const nodes24 = nodes.filter((n) => n.label === p);
+	}
+
+	return {
+	        nodes: nodes,
+		links: links,
+	};
+}
+
+export function distance_groups(shape) {
+    // get list of other nodes by distance
+    // sort them and dump them out
+    const dists = {};
+
+    shape.nodes.map((n) => {
+        const draw = dist(shape.nodes[0], n);
+        const dtrunc = round_dist(draw);
+        if( !(dtrunc in dists) ) {
+            dists[dtrunc] = [];
+        }
+        dists[dtrunc].push(n.id);
+    });
+    return dists; 
+}
+
+export function insc600_layers(cell600) {
+    const layers = distance_groups(cell600);
+/*    const sorted = Object.keys(layers).sort((a,b) => a - b);
+    for( const d of sorted ) {
+        const ids = layers[d].map((n) => n.id);
+        console.log(`Layer at distance ${d}`);
+        console.log(ids);
+    } */
+    return layers;
+}
+
+export function neighbours(shape, nid) {
+    const links = shape.links.filter((l) => l.source === nid || l.target == nid );
+    const nodes = links.map((l) => {
+        if( l.source === nid ) {
+            return l.target;
+        } else {
+            return l.source;
+        }
+    });
+    return nodes;
+}
+
+export function neighbours_in_subset(shape, subset, nid) {
+    // shape = nodes, links
+    // subset = a list of ids
+    // n = an id
+    // returns all of n's neighbours which are in subset
+
+    const all_nbors = neighbours(shape, nid);
+    return all_nbors.filter((n) => subset.includes(n));
+}
+
+export function face_vertices(shape, f1, f2, f3) {
+    // for f1/f2/f3 forming a triangular face, return the two vertices of the
+    // adjacent tetrahedra
+
+    const n1 = neighbours(shape, f1).filter((n) => n !== f2 && n !== f3);
+    const n2 = neighbours(shape, f2).filter((n) => n !== f1 && n !== f3);
+    const n3 = neighbours(shape, f3).filter((n) => n !== f1 && n !== f2);
+
+    const ns = n1.filter((n) => n2.includes(n) && n3.includes(n));
+    return ns;
+}
+
+export function layer_neighbours(cell600, layer) {
+    console.log("Layer neighbours");
+    for( const n of layer ) {
+        console.log(`n = ${n}`);
+        const nbors = neighbours_in_subset(cell600, layer, n);
+        console.log(`   Vertex ${n} neighbours: ` + JSON.stringify(nbors));
+    }
+}
+
+export function layer_two(cell600) {
+    const faces = [
+        [ 419, 223, 253 ],
+        [ 419, 253, 331 ],
+        [ 419, 331, 427 ],
+        [ 419, 427, 339 ],
+        [ 419, 339, 223 ],
+        [ 253, 223, 265 ],
+        [ 331, 253, 473 ],
+        [ 427, 331, 539 ],
+        [ 339, 427, 555 ],
+        [ 511, 339, 223 ],
+        [ 223, 511, 265 ],
+        [ 253, 265, 473 ],
+        [ 331, 473, 539 ],
+        [ 427, 539, 555 ],
+        [ 339, 555, 511 ],
+        [ 393, 265, 511 ],
+        [ 393, 473, 265 ],
+        [ 393, 539, 473 ],
+        [ 393, 555, 539 ],
+        [ 393, 555, 511 ]
+    ];
+
+    for ( const face of faces ) {
+        const n2 = face_vertices(cell600, face[0], face[1], face[2]);
+        //console.log(face);
+        console.log(n2.filter((n) => n !== 27)[0]);
+    }
+}
+
+
+/*const cell600 = make_one_600cell();
+const layered = insc600_layers(cell600);
+
+for( const d in layered ) {
+    console.log(`dist = ${d}`);
+    layer_neighbours(cell600, layered[d]);
+}
+
+*/