Can a Yantra force a desirable event or occurrence to take place?
No. A Yantra is above all a spiritual system of energy and it cannot be either subverted for selfish ends that is not in harmony with the larger universe or tricked into conferring underserved benefits. All Yantras are to be understood as enhancing potential that exists. They cannot force something to happen that is against natural karma. Yantras aid and assist in bringing about a desirable outcome, but they cannot force something to take place. You cannot force somebody to love you, you cannot force good luck and prosperity, but Yantras will speed up the process if it exists as a potential, they help in reducing the time before something good manifests, they help in removing obstacles that may exist. Yantras cannot force something to happen because it is desired; they enable it to be manifest if it is karmically deserved. Yantras must always be handled with the utmost respect and consideration as careless and cavalier treatment will quickly reduce their power.