The documentation has several examples of how to plot several traces of the same length on either the same or different plots and it is easier to overlook the fact that one can modify an existing plot also with the command as stated at the top of the page linked above
plot!(plt, args...; kw...) # modifies Plot `plt`
pn are plots,
plot(p1, p2, ..., pn) will plot them with a default layout.
For as much as this sound ridiculous, not knowing this was my only reason to stay clear of Plots.jl.
A question: what is the reason not to throw an error when plotting
y of different length, but to wrap the data around?