The graph of height versus time would be a single, smooth curve passing through the given points and then repeating its shape over and over. Visually, starting at the initial high point, the curve would sweep down to the low point, then rise back up to a high point, fall again, and so on in a regular, wave‐like pattern.
There are no sharp corners or breaks—just a continuous “up–down–up–down” motion of fixed size and time.
To capture that periodic, oscillating behavior one often uses functions that rise and fall smoothly—most commonly sine or cosine curves—to model the height of a pendulum over time.