Listener's exact position is unclear in Two Sources screen

[matthew-blackman]

In the java version of the sim, the image of the person in the Two Sources screen makes it (relatively) clear that the person's ear is the location being represented by the sim audio. See screenshot:

This is helpful for showing students the details of the interference pattern, where behavior can change quickly in short distances. The current version of the Sound sim makes it unclear which point is being represented:

I recommend adding a small addition to the graphics of the person, such as a dot or an 'x' marking the location that is represented by the sim audio.

[matthew-blackman]

An 'X' has been added to the image of the person, showing the location represented by the sim audio.

Closing.