Today’s Apps Gone Free: Knots 3D, Plugs of the World, BrainWave Hangover Relief and More

Learn to tie knots, find out which plugs and adapters to bring along on your travels, and relieve hangover symptoms with today’s collection of apps and games.

All app prices are subject to change at any time and without notice regardless of stated free duration. Price changes are solely under the control of the developers.

Universal:

Knots 3D ($1.99 → Free, 52.6 MB): Learn how to tie 118 different types of knots with this detailed reference app. Almost everyone will find Knots 3D to be handy at some point.

With Knots 3D, anyone can learn to tie a knot. You’re able to watch each knot tie itself, and you can pause or adjust the speed of the animation at any time. You can also rotate each knot 360 degrees, and zoom in using multitouch gestures. Knots can be broken down by category or class, and they can be added to favorites for quick reference.

Knots 3D is available for free for a limited time. It has a 5-star rating with a total of 3018 ratings.

Peter Potato ($1.99 → Free, 70.0 MB): Help Peter Potato build up his confidence in this story-based adventure. Fans of mini-games will get a kick out of this quirky tale.

Peter Potato’s adventure will test your speed, skill, memory, rhythm, and intellect through 70 fast-paced mini-games. The charming and quirky story sets up each mini-game. The dialogue is not only amusing, it’s also loaded with more than 150 vegetable facts. Along the way you’ll be able to unlock new characters, clothes, and accessories.

Peter Potato is available for free for a limited time. It has a 4-star rating with a total of 90 ratings.

Plugs of the World ($2.99 → Free, 10.2 MB): Find out which plugs and adapters to bring along on your travels with this reference app. It’s a must for world travelers.

Plugs of the World includes information about wall plugs, sockets, and voltage in over 250 countries and regions across the world. You’re able to search for a specific country or region by name or browse through the list. You’re also able to favorite countries and regions for quick access later on. You’re able to share wall plug and socket information via email, Facebook, or Twitter.

Plugs of the World is available for free for a limited time. It has a 4.5-star rating with a total of 32 ratings.

BrainWave Hangover Relief – Advanced Binaural Brainwave Entrainment ($0.99 → Free, 77.8 MB): Relieve hangover symptoms by listening to low frequency waves with this health app. It provides a great way to relax your mind.

BrainWave Hangover Relief offers advanced brainwave entrainment therapy. You’re able to select from daytime and evening programs, and choose a soothing background sound to accompany them. Then hit play and allow the app to sync your brainwaves to the deeply relaxing low frequency alpha and theta waves. The app also allows you to adjust the signal intensity and save your settings for later use.

BrainWave Hangover Relief – Advanced Binaural Brainwave Entrainment is available for free for a limited time. It has a 3.5-star rating with a total of 40 ratings.

Slide Tetromino Premium ($0.99 → Free, 57.9 MB): Collect keys by melting the ice around them in Slide Tetromino. It’s for fans of sliding puzzle games.

Each level includes a single flame, movable pieces, and very little room to operate in. It’s up to you to slide the pieces every which way in order to create a path from the frozen key to the flame. Levels aren’t timed, but your moves will be counted. The game includes a total of 100 levels.

Slide Tetromino Premium is available for free for a limited time. It has a 4.5-star rating with a total of 320 ratings.

Monster Math 2 Multiplayer – Free Mathematics Duel and Homework Drills for Elementary School ($2.99 → Free, 55.7 MB): Children can compete with each other in math duels in Monster Math 2 Multiplayer. It’s perfect for home and classroom settings.

Today only: Unlock everything Monster Math 2 Multiplayer has to offer free of charge! Simply tap the “Unlock Full Version” icon at the bottom of the main screen and choose the in-app purchase on the following screen. You’ll be asked to confirm your action by entering the code supplied to you. Then enjoy!

With Monster Math 2 Multiplayer, no one is left out. It allows children from grades one through five compete against one another in math duels while keeping the difficulty level of the problems aligned. This ensures a balanced playing field. Children are able to compete locally on the same screen, in the same room via Bluetooth, online via Game Center, or against the computer. While having fun they will be practicing and learning over 40 skills including addition, subtraction, division, multiplication, factors, and prime numbers. The game also includes detailed stat tracking.

Monster Math 2 Multiplayer – Free Mathematics Duel and Homework Drills for Elementary School is available for free today only (07/07). It has a 4.5-star rating with a total of 74 ratings.

That concludes today’s issue of Apps Gone Free. If you like staying on top of these daily deals, don’t forget to check out our free AppsGoneFree app. It provides all the deals each day, and even an archive of past deals that are still active.

Developers:

If you are a developer who would like to get your app included in our “Apps Gone Free” daily lists, here’s our basic set of rules:

It must have at least a three-star average rating at the time it goes free.
The app must not have been free numerous times (3+) over the last six months.
The free version of your app must not include ads.

To submit an app, simply send a request to tyler@appadvice.com with the subject “Apps Gone Free.” Please include the name of the app, a link to it in the App Store, when and for how long you intend to offer the app for free, and anything else you would like to share. We will take it from there.