A queue, one step at a time.
A queue processes jobs in arrival order. Try the small model below. Every control, graphic and readout reads from the same queue.
The rule stays simple.
The first job that arrives is the first one processed. The readout and figure use the same array, so they stay in agreement.
Use a wrapper like this for more ambitious SVG and canvas work. Loami provides the reading environment; your figure owns its model and controls.
<loam-figure>
<!-- Your SVG, canvas or HTML -->
</loam-figure>