This example uses OpenLayers v10.9.0. The latest is v.
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#### Regular Shapes

vector 86 symbol 3 regularshape 2 style 27 square 1 rectangle 3 cross 1 star 1 triangle 1 x 1

#####

Example of some Regular Shape styles.

This example shows how several regular shapes or symbols (representing `x`, `cross`, `star`, `triangle`, `square` and `stacked`) can be created. A `rectangle` is produced by scaling a square created without rotation. Style `stacked` represents possility to stack multiple shapes with offset

##### main.js

    import Feature from 'ol/Feature.js';
    import Map from 'ol/Map.js';
    import View from 'ol/View.js';
    import Point from 'ol/geom/Point.js';
    import VectorLayer from 'ol/layer/Vector.js';
    import VectorSource from 'ol/source/Vector.js';
    import Fill from 'ol/style/Fill.js';
    import RegularShape from 'ol/style/RegularShape.js';
    import Stroke from 'ol/style/Stroke.js';
    import Style from 'ol/style/Style.js';

    const stroke = new Stroke({color: 'black', width: 2});
    const fill = new Fill({color: 'red'});

    const styles = {
      'square': new Style({
        image: new RegularShape({
          fill: fill,
          stroke: stroke,
          points: 4,
          radius: 10,
          angle: Math.PI / 4,
        }),
      }),
      'rectangle': new Style({
        image: new RegularShape({
          fill: fill,
          stroke: stroke,
          radius: 10 / Math.SQRT2,
          radius2: 10,
          points: 4,
          angle: 0,
          scale: [1, 0.5],
        }),
      }),
      'triangle': new Style({
        image: new RegularShape({
          fill: fill,
          stroke: stroke,
          points: 3,
          radius: 10,
          rotation: Math.PI / 4,
          angle: 0,
        }),
      }),
      'star': new Style({
        image: new RegularShape({
          fill: fill,
          stroke: stroke,
          points: 5,
          radius: 10,
          radius2: 4,
          angle: 0,
        }),
      }),
      'cross': new Style({
        image: new RegularShape({
          fill: fill,
          stroke: stroke,
          points: 4,
          radius: 10,
          radius2: 0,
          angle: 0,
        }),
      }),
      'x': new Style({
        image: new RegularShape({
          fill: fill,
          stroke: stroke,
          points: 4,
          radius: 10,
          radius2: 0,
          angle: Math.PI / 4,
        }),
      }),
      'stacked': [
        new Style({
          image: new RegularShape({
            fill: fill,
            stroke: stroke,
            points: 4,
            radius: 5,
            angle: Math.PI / 4,
            displacement: [0, 10],
          }),
        }),
        new Style({
          image: new RegularShape({
            fill: fill,
            stroke: stroke,
            points: 4,
            radius: 10,
            angle: Math.PI / 4,
          }),
        }),
      ],
    };

    const styleKeys = [
      'x',
      'cross',
      'star',
      'triangle',
      'square',
      'rectangle',
      'stacked',
    ];
    const count = 250;
    const features = new Array(count);
    const e = 4500000;
    for (let i = 0; i < count; ++i) {
      const coordinates = [2 * e * Math.random() - e, 2 * e * Math.random() - e];
      features[i] = new Feature(new Point(coordinates));
      features[i].setStyle(
        styles[styleKeys[Math.floor(Math.random() * styleKeys.length)]],
      );
    }

    const source = new VectorSource({
      features: features,
    });

    const vectorLayer = new VectorLayer({
      source: source,
    });

    const map = new Map({
      layers: [vectorLayer],
      target: 'map',
      view: new View({
        center: [0, 0],
        zoom: 2,
      }),
    });

    const colors = ['blue', 'green', 'yellow', 'aqua', 'red'];
    let currentColor = 0;

    document.getElementById('color-changer').addEventListener('click', function () {
      styles.square
        .getImage()
        .setFill(new Fill({color: colors[currentColor % colors.length]}));
      vectorLayer.changed();
      currentColor++;
    });

##### index.html

    <!DOCTYPE html>
    <html lang="en">
      <head>
        <meta charset="UTF-8">
        <title>Regular Shapes</title>
        <link rel="stylesheet" href="node_modules/ol/ol.css">
        <style>
          .map {
            width: 100%;
            height: 400px;
          }
        </style>
      </head>
      <body>
        <div id="map" class="map"></div>
        <div>
          <button id="color-changer">Change Square Colors</button>
        </div>

        <script type="module" src="main.js"></script>
      </body>
    </html>

##### package.json

    {
      "name": "regularshape",
      "dependencies": {
        "ol": "10.9.0"
      },
      "devDependencies": {
        "vite": "^3.2.3"
      },
      "scripts": {
        "start": "vite",
        "build": "vite build"
      }
    }