求助帖，我最近在学processing
这是第四章变量的作业。
要求圆大小缩放，然而我写的程序，只有1，4两个圆在键盘按了以后会变，2，3两个圆都不变了。
这是为什么？以下是程序：
float g1=255;
float b1=255;
float b2=255;
float r3=255;
float g3=255;
float g4=255;
float l1=0;
float w1=0;
float l2=0;
float w2=0;
float l3=0;
float w3=0;
float l4=0;
float w4=0;
void setup(){
size(600,400);
background(255);
}
void draw(){
drawRect();
drawEllipse1();
drawEllipse2();
drawEllipse3();
drawEllipse4();
}
void drawRect(){
stroke(0);
fill(0);
rect(0,0,300,200);
rect(300,200,300,200);
}
void drawEllipse1(){
noStroke();
fill(255,g1,b1);
g1=g1-1;
b1=b1-1;
ellipse(150,100,l1,w1);
if (w1>200){
w1=w1+0;
} else if (w1<=200){
w1=w1+1;
}
if (l1>300){
l1=l1+0;
} else if (l1<=300){
l1=l1+1;
}
}
void drawEllipse2(){
noStroke();
fill(255,255,b2);
b2=b2-1;
ellipse(450,100,l2,w2);
if (w2>200){
w2=w2+0;
} else if (w2<=200){
w2=w2+1;
}
if (l2>300){
l2=l2+0;
} else if (l2<=300){
l2=l2+1;
}
}
void drawEllipse3(){
noStroke();
fill(r3,g3,255);
if (r3>100){
r3=r3-1;
} else if (r3<=100){
r3=100;
}
ellipse(150,300,l3,w3);
if (w3>200){
w3=w3+0;
} else if (w3<=200){
w3=w3+1;
}
if (l3>300){
l3=l3+0;
} else if (l3<=300){
l3=l3+1;
}
}
void drawEllipse4(){
noStroke();
fill(255,g4,255);
g4=g4-1;
ellipse(450,300,l4,w4);
if (w4>200){
w4=w4+0;
} else if (w4<=200){
w4=w4+1;
}
if (l4>300){
l4=l4+0;
} else if (l4<=300){
l4=l4+1;
}
}
void keyPressed(){
w1=w1*-1;
l1=l1*-1;
w2=w2*-1;
l2=l2*-1;
w3=w3*-1;
l3=l3*-1;
w4=w4*-1;
l4=l4*-1;
}

void draw()里面加入background(255)即可
void draw(){
background(255);
drawRect();
drawEllipse1();
drawEllipse2();
drawEllipse3();
drawEllipse4();
}