# Expanding circles, how do I do it?
**URL:** https://discourse.processing.org/t/expanding-circles-how-do-i-do-it/9305
**Category:** Coding Questions
**Created:** [March 14, 2019, 6:04pm UTC](https://discourse.processing.org/t/expanding-circles-how-do-i-do-it/9305 "2019-03-14T18:04:57Z")
**Posts on this page:** 9
**Page:** 1
### Author:  [@fraxinus](https://discourse.processing.org/u/fraxinus)
#### Post date: [March 14, 2019, 6:04pm UTC](https://discourse.processing.org/t/expanding-circles-how-do-i-do-it/9305/1 "2019-03-14T18:04:57Z")
How do I make a circle that starts as a dot and then keeps getting bigger until it disappears?
Also then, how would I have more circles continuously appearing from that same point one after the other so I get what looks like a wave expanding in all directions viewed from above?
---
### Author:  [@Chrisir](https://discourse.processing.org/u/Chrisir)
#### Post date: [March 14, 2019, 6:10pm UTC](https://discourse.processing.org/t/expanding-circles-how-do-i-do-it/9305/2 "2019-03-14T18:10:45Z")
Hello and welcome here!
Please read this and build your animation from here:
[https://www.processing.org/tutorials/overview/](https://www.processing.org/tutorials/overview/)
Look at ellipse to get started:
[https://www.processing.org/reference/ellipse\_.html](https://www.processing.org/reference/ellipse_.html)
you need to store width and height of the ellipse. Use a variable **d** for both
increase **d** : d=d+1;
then show your animation sketch so far
Chrisir
---
### Author:  [@fraxinus](https://discourse.processing.org/u/fraxinus)
#### Post date: [March 14, 2019, 6:40pm UTC](https://discourse.processing.org/t/expanding-circles-how-do-i-do-it/9305/3 "2019-03-14T18:40:01Z")
Thanks!
Here is my progress so far:
float d = 1;
void setup() {
size(640, 360);
stroke(255, 204, 0);
noFill();
}
void draw() {
background(0);
d = (d+1);
ellipse(200, 200, d, d);
}
---
### Author:  [@Chrisir](https://discourse.processing.org/u/Chrisir)
#### Post date: [March 14, 2019, 7:22pm UTC](https://discourse.processing.org/t/expanding-circles-how-do-i-do-it/9305/4 "2019-03-14T19:22:06Z")
nicely done!
Remember to hit **ctrl-t** in processing to get auto-format (indents)
**Next step**
Now, you want to have different circles with same center
This calls for arrays!
an Array is a list of values.
so before `setup()`:
```auto
int[] ds = new int[1000]; // wrong! d, not ds ;-)
int timer;
int max=0;
```
in `draw()`:
```auto
for(int i = 0; i1400) {
max=max+1;
timer = millis();
}
```
Chrisir π
---
### Author:  [@fraxinus](https://discourse.processing.org/u/fraxinus)
#### Post date: [March 14, 2019, 7:47pm UTC](https://discourse.processing.org/t/expanding-circles-how-do-i-do-it/9305/5 "2019-03-14T19:47:33Z")
I got this error. What does it mean?
---
### Author:  [@Chrisir](https://discourse.processing.org/u/Chrisir)
#### Post date: [March 14, 2019, 7:49pm UTC](https://discourse.processing.org/t/expanding-circles-how-do-i-do-it/9305/6 "2019-03-14T19:49:46Z")
please hit **ctrl-t** in processing
please post your entire code as text
Do you have this:
```auto
int[] d = new int[1000];
```
(I had `ds` there falsely)
---
### Author:  [@fraxinus](https://discourse.processing.org/u/fraxinus)
#### Post date: [March 14, 2019, 7:52pm UTC](https://discourse.processing.org/t/expanding-circles-how-do-i-do-it/9305/7 "2019-03-14T19:52:12Z")
ah, I removed the s and now itβs working. Cool!! Thank you so much!
Here is the code so far:
```auto
int[] d = new int[1000];
int timer;
int max=0;
void setup() {
size(1500, 700);
}
void draw() {
background(220);
stroke(0);
fill(0);
rect(100, 100, 300, 400);
noFill();
stroke(255, 100, 0);
//ellipse(200, 200, d, d);
//d=d+5;
for (int i = 0; i1400) {
max=max+1;
timer = millis();
}
}
```
---
### Author:  [@Chrisir](https://discourse.processing.org/u/Chrisir)
#### Post date: [March 14, 2019, 7:57pm UTC](https://discourse.processing.org/t/expanding-circles-how-do-i-do-it/9305/8 "2019-03-14T19:57:59Z")
well done!
please read the code and understand
- arrays,
- timer and
- why we get slowly more circles.
The sketch will crash after a few minutes. How many? Why?
What does `max` do?
**Auto-Format in processing**
hit **ctrl-t** in processing (or menue **Edit | Auto-format** )
**Formatting in the Forum**
Anyway, in the forum after pasting, please mark your code with the mouse and click `` in the command bar
- to show your code formatted as code when posting in the forum
Chrisir π
---
### Author:  [@fraxinus](https://discourse.processing.org/u/fraxinus)
#### Post date: [March 14, 2019, 8:05pm UTC](https://discourse.processing.org/t/expanding-circles-how-do-i-do-it/9305/9 "2019-03-14T20:05:26Z")
Will do!
Thanks!! π