Replace appengine/pond/duck/default-ducks.js in blocklyGAMES to make ducks editable.

ducks.js

/**
 * @license
 * Copyright 2020 Google LLC
 * SPDX-License-Identifier: Apache-2.0
 */

/**
 * @fileoverview Demo ducks for Pond battle.
 * @author fraser@google.com (Neil Fraser)
 */
'use strict';

const bzz=`
<xml>
  <block type="pond_cannon" x="70" y="70">
    <value name="DEGREE">
      <shadow type="pond_math_number">
        <mutation angle_field="true" />
        <field name="NUM">0</field>
      </shadow>
    </value>
    <value name="RANGE">
      <shadow type="pond_math_number">
        <mutation angle_field="false" />
        <field name="NUM">70</field>
      </shadow>
    </value>
  </block>
</xml>`;

var DUCKS = [
  {name: "Romut", id: "default", editable: true, blockly: `
<xml>
  <block type="pond_cannon" x="70" y="70">
    <value name="DEGREE">
      <shadow type="pond_math_number">
        <mutation angle_field="true" />
        <field name="NUM">0</field>
      </shadow>
    </value>
    <value name="RANGE">
      <shadow type="pond_math_number">
        <mutation angle_field="false" />
        <field name="NUM">70</field>
      </shadow>
    </value>
  </block>
</xml>`, compiled: "cannon(0, 70);", competent: false},
  {name: "Marut", id: "rook", editable: true, compiled: 'cannon(0,70);',blockly:bzz},
  {name: "Counter", id: "counter", editable: false, compiled: `
/* counter */
/* scan in a counter-clockwise direction (increasing degrees) */
/* moves when hit */

var range;
var last_dir = 0;

var res = 2;
var d = damage();
var angle = Math.random() * 360;
while (true) {
  while ((range = scan(angle, res)) != Infinity) {
    if (range > 70) { /* out of range, head toward it */
      drive(angle, 50);
      var i = 1;
      while (i++ < 50) /* use a counter to limit move time */
        ;
      drive (angle, 0);
      if (d != damage()) {
        d = damage();
        run();
      }
      angle -= 3;
    } else {
      while (!cannon(angle, range))
        ;
      if (d != damage()) {
        d = damage();
        run();
      }
      angle -= 15;
    }
  }
  if (d != damage()) {
    d = damage();
    run();
  }
  angle += res;
  angle %= 360;
}

/* run moves around the center of the field */
function run() {
  var i = 0;
  var x = getX();
  var y = getY();

  if (last_dir == 0) {
    last_dir = 1;
    if (y > 51) {
      drive(270, 100);
      while (y - 10 < getY() && i++ < 50)
        ;
      drive(270, 0);
    } else {
      drive(90, 100);
      while (y + 10 > getY() && i++ < 50)
        ;
      drive(90, 0);
    }
  } else {
    last_dir = 0;
    if (x > 51) {
      drive(180, 100);
      while (x - 10 < getX() && i++ < 50)
        ;
      drive(180, 0);
    } else {
      drive(0, 100);
      while (x + 10 > getX() && i++ < 50)
        ;
      drive(0, 0);
    }
  }
}`
},
  {name: 'Ocut', id: 'sniper', editable: true, compiled: "cannon(0,70);", blockly:bzz}
];