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        document.getElementById('addSupplyDepot').addEventListener('click', function(event) {
            var newElement = document.createElementNS("http://www.w3.org/2000/svg", 'circle');
            newElement.setAttribute('cx', '300');
            newElement.setAttribute('cy', '300');
            newElement.setAttribute('r', '20');
            newElement.setAttribute('class', 'supply-depot');
            svg.appendChild(newElement);
        });