How to access a variable in compositionReady?

On my compositionReady I have

sym.setVariable("X", 0);

On the stage a Rectangle and a textfield called Result. For the .click on the Rectangle I have

sym.setVariable("X", "X" + 1);

sym.$("Result").html(sym.getVariable("X"));

What I want to happen is to add 1 to X everytime I click the Rectangle and print the result. But this method only prints out X1 each time I click the Rectangle.

So what I thought was because "X" is a string I should use X instead but this doesn't work. Nor using this will work

compositionReady:

var X = 0;

Rectangle.click:

sym.setVariable(X, X + 1);

sym.$("Result").html(sym.getVariable(X));

What is the correct way to approach this? I also don't have any luck with sym.getComposition().getStage().getVariable(X);