EtchAsketch code modification

I am working on a science project with my son that involves generating a force as a function of time plot. My idea is to modify the EtchaSketch code for this purpose. Accordingly, I have replaced the Littlebits pressure sensor with one of the dimmers to be plotted along the y-axis (a1). I have the calibration to convert the voltage into force. However, I need to measure time on the x-axis. I would like to know how I could modify the EtchaSketch code to measure time along the x-axis (a0). Moreover, I would like to show the numerical values on the vertical and horizontal axes and keep the measured signal. Thx