This is a Progressive Web App (PWA) which means it can be installed on most devices and used even when you can't connect to the internet. Look for the install button in your browser. It is usually on the URL bar as ⊕ or in the triple dot options ⋮ and look for "Install app/FastStereo".
Turn on Triangle Guides and use the small black triangle guides at the top of the stereogram to help you. A favorite technique of ours is put the picture right up to our nose and then look beyond it. Things will be blurry at first. Slowly move the picture away from your nose until you see the two triangle guides become three with one exactly in the middle. That means you are close to the correct focus point and if you are lucky the 3D picture will start forming in your brain. Results will vary. Some people have a knack at them while others have spent hours and end up thinking their friends are just playing a prank on them. You will probably also have better luck on a bigger screen like a tablet, laptop, or PC; it is very hard to do on a small phone screen.
The timer only counts down when you are actually viewing the stereogram. It is paused when you are selecting your answer or entering a custom word. The total game time in stereograms is 10 minutes. Remember to click when you solve one to stop the timer and help increase your final score.
If you have the Custom Words option turned on you will sometimes be prompted to enter your own short custom words. We recommend you keep these under 9 characters. These will only sometimes be used for both correct and incorrect answers but the chances of them appearing will be higher than for the installed words. If you turn off the Custom Words option they will not be used at all.
FastStereo is what is know as a Progressive Web App to techies. It means it really runs in your web browser even if you installed it. So if you clear your browser data or your browser decides to clear out space, FastStereo might lose it's saved data. Sorry, there is not much we can do about it.