Anyone wanting to try the effect of flashing goggles (aka Light and Sound machines) without actually buying one, well, just look for the torch application on your smartphone, it might be that it provides an option for strobing lights.
The one that I use is called "Nexus One Torch" for Android by Ben Buxton, but there might be others.
Just set the strobing frequency to 7 Hz (or any other frequency between 5-20 Hz), CLOSE YOUR EYES and put the phone in front of your face, next to your eyes. If you keep it long enough you will start to see fractals.
The effect of course isn't as strong as true flashing goggles because smartphones have only one led light (goggles have several).
And if you don't have a smartphone: choose a sunny day, CLOSE YOUR EYES and stare toward the sun. Now open the palm of your hand (fingers wide apart) and continuously move it up and down in front of your eyes. With this method the effects are stronger because the light from the sun is more powerful than a smartphone's led, but one gets tired very quickly of moving the hand up and down.
A note of caution: strobing lights are known to trigger to seizures in some subjects, so take all the precautions and stop doing it if you see something going wrong!
Also, it's interesting to see how the fractals change their form when you are under the effect of entheogens.