How to create a small field that cycles through a series of images. (using Acrobat Pro)

Question

Using Acrobat Pro, we need to use a small field to track student progress.  With successive mouse clicks, the field would cycle through: 
-- a number (that identifies an element of study),
-- same number surrounded by a circle (indicates element is assigned to the student),
-- same number with a check mark (indicates element was completed by the student),
-- back to the original number.
This could probably be handled by cycling through a series of small images when the user clicks on the field.   
The "Check Box" field allows only a check to be added to the field.  It does not allow the circle and does not cycle through multiple states. 
The "Text Box" field might allow this capability, but if so we are not able to configure it properly.  
Any solutions?   Thanks!

Answer 1

Thanks Michael,
The information at the link you provided enabled us to create a button that cycles through a series of ASCII characters. 
This us useful, but we need to cycle through a series of images.  A more difficult problem. 
FYI, an example of the javascript that cycles through a series of ASCII characters is shown below.  (The "else" statement pertaining to a null "" buttonGetCaption state is used to initiate an initial state of "1" for the button when the form is first opened.). 
if
(event.target.buttonGetCaption()=="1"+"\u2714") {
    event.target.buttonSetCaption("1");
    event.target.textColor = color.black; }
else if (event.target.buttonGetCaption()=="") {
    event.target.buttonSetCaption("1");
    event.target.textColor = color.black; }
else if (event.target.buttonGetCaption()=="1P") {
    event.target.buttonSetCaption("1"+"\u2714");
    event.target.textColor = color.green; }
else if (event.target.buttonGetCaption()=="1") {
    event.target.buttonSetCaption("1P");
    event.target.textColor = color.red; }
loop
Again, we are still looking for a way to cycle through a series of images so any help with that problem would be appreciated.