SOURCE

let x=10
let z=180
function setup(){
createCanvas(500,500);
background(0);
colorMode(HSB,300,100,100);
} 
function draw(){
strokeWeight(x)
stroke(z,80,80);
if(mouseIsPressed){
line(mouseX,mouseY,pmouseX,pmouseY)}
if(keyIsPressed){
if(key=='q'||key=='Q')
z-=1
if(key=='w'||key=='W')
z+=1
}
if(keyIsPressed){
if(key=='A'||(key=='a'))
x-=0.1
if(key=='S'||(key=='s'))
x+=0.1
} 
}