In USolver, linking between elements and spreadsheet cells can be either one-way or bi-directional. One-way linking allows data to flow in a single direction—for example, from cells into element properties such as position, size, or color, or from events into cells to log user actions or system states. This setup is ideal for reactive designs where elements respond to underlying data or behavior. Bi-directional linking, on the other hand, enables two-way data flow: changes in the cell update the element, and user interactions with the element—such as typing in an input field or adjusting a slider—immediately update the linked cell.