periodic symbolic matlab function

say I want to make a symbolic function (I mean a function of a symbolic variable x), but it's periodic. Imagine a rectangle that repeats itself along the x axis. But I want it symbolic, not in function of an array x. How to implement it? I can use a for loop but the loop is limited! And there is no such thing as "for i=1:inf"

Answer 1

[Walter Roberson]

xm = mod(x,AppropriatePeriod);

and then use xm instead of x in your formula

Answer 2

[Youssef]

can you please write down a couple of lines code using mod and ezplot?

[Walter Roberson]

Take the implicit example

ezplot('x^2-y^4')

and modify to

ezplot('mod(x,8)^2-y^4')

to get it to repeat every 8