So maybe you've stumbled across an unexpected rotation/twist in one of your TGM games and decided to ask for clarification on IRC or the forums. Since explaining tetris manoeuvres in words can be ambiguous and imprecise you come to the conclusion that you should draw a diagram in Fumen (http://fumen.zui.jp/) like the ones you'd seen being posted occasionally. After all, how hard could it be? Because I've seen even strong grandmasters (*cough* @Qlex *cough*) confused by its interface, I thought it would be a good idea to write a short guide that explains all of Fumen's features. I will also explain how Fumen can help you familiarise yourself with the rotation system or learn the input for certain moves. Ready? Go! "Help, I can't read moonrunes!" To switch to an english translation click on the "Add-on" link on the bottom and then click the "english.js" link or just append "#english.js" to the URL manually. Given that the majority of players on here use the elegant Arika Rotation System (ARS) go ahead and uncheck "Guideline". Note how this changes the colours from being an eye sore to the pleasing ARS colours. Drawing a field Drawing is very straightfoward. Just click an empty cell in the grid to add a block or click a filled cell to remove a block. You can also hold the left mouse button down and move the mouse around to repeat that action for other cells. If you want to draw a pretty, colourful stack for some reason, click one of the other radio buttons at the very top. The "Fill Row" checkbox provides a shortcut for drawing a stack by allowing you draw filled lines leaving a hole in the cell you clicked at (you can drag your mouse around for this as well). In order to remove whole lines in this mode either click the hole in an otherwise filled line or click twice. The buttons "Up", "Left", "Right", "Down" shift the playfield around in the respective directions. Placing Tetrominos Now let's have a look at the next section in order to place some good ol' tetrominos. Ignore the "Quiz" button for now, I'll get to that later. The radio buttons represent the tetrominos at different states with the first row (with the darker background) being the neutral state (unless you forgot to uncheck Guideline, then it's the third row). Moving down one row means rotating counterclockwise. Note that you can see how the piece would normally enter the playfield in each state by hovering the mouse over the radio buttons; with one important exception which I reckon is a bug: Fumen (version 1.15a) will show that an IRS'd I piece spawns in column 5, but it really spawns in column 6 in the game. Placing pieces works by selecting a radio button and clicking into the grid. Gravity is immediately applied if the "Lock" checkbox is active. It's only possible to have one active pieve per frame, so trying to throw in another piece will replace it, but don't worry, we'll get to how frames work in a minute. Unchecking "Mino" removes the active piece in case you don't want it in your frame anymore. The "Rise" and "Mirror" checkboxes only work in combination with the "Lock" checkbox (which causes the active piece to be locked by the next frame); they will mirror the playfield or shift the playfield up by one respectively. With all that out of the way, let's get to one of the more interesting parts of Fumen: movement and rotation! Manipulating Tetrominos Manipulating the active piece (from now on referred to as 'AP') is what all those odd-looking buttons underneath the tetromino radio buttons are for. Their purposes are (from left to right): move AP left by one; either soft drop or lock & immediately go to next frame depending on whether the AP is floating in the air or not; sonic drop (or hard drop with SRS rules / "Guideline" checked); move AP right by one; rotate counterclockwise; rotate clockwise; hold (only works in combination with the "Quiz" button or custom piece sequences, more on that later) For maximum convenience click inside the small input box next to the hold button (only enabled if there's an AP) and watch the button captions change to hotkeys you can press to do the respective actions. You can hold those keys down, e.g. for a pseudo-"DAS". All the other number keys except 0 will also rotate, so it's possible to only use the numpad for everything. So why is this so great? Simples, because it allows you to check your intuition on twists or more generally on how the rotation system works and it also helps with optimising the input for a move or finding alternative moves! A few examples: Note how I emulate a synchro move (rotation and movement in the same frame - either by inputting it within the same frame or by using DAS) in the first two by unchecking "Lock" to disable gravity for a moment. One minor caveat: Fumen uses TGM3's version of ARS (i.e. the I piece can wall kick, the T and I piece can floor kick), so be sure to know the differences between the two ARS variants. Working with frames Clicking the "Next" button while you're at the last (or only) frame will duplicate it and increase the frame counter (see the numbers after "Frame"; you can use the input field to jump to a specific frame) by one. You're now working on the new frame which can only differ in that the previously active piece is now locked and "Rise" and "Mirror" took effect. If you're not at the last frame, "Back", "Next" and the buttons next to them will move you through your frames. It's important to realise that changes you make to earlier frames will not carry over to the following frames! "Clear to end" will remove all the frames after the current one, which allows you to fix mistakes. Lastly, there's an input box underneath "Caption" where you can put a caption that'll be displayed for that frame with a green background (unless it's empty) and by default for every following frame with a white background. Sharing the diagram If you're satisfied with all your frames, hit the "Output Data" button (having "Auto Output" checked is like hitting the button after every change). This will fill the text fields at the bottom with URLs for the diagram that you can send to all your friends. The "URL" one links to your diagram in an editor whereas "VIEW" gives a smaller, more minimalistic view with only buttons to move through the frames and an "Edit" link to open the diagram in the editor. "LIST" is very similar to "VIEW" with the only difference that all the frames are shown at once, next to each other. The astute observer will notice that all these URLs only differ in the first letter of the query string (after the question mark), so if you're anything like me and someone sends you a rather long Fumen in edit or list mode, you'll want to replace that letter with a 'd'. The "Make TinyURL!" button sends you to tinyurl.com and gives you a shortened link. If you want to start with a fresh new diagram, either refresh the page or click "New Data"; the latter will even ask for confirmation which refreshing doesn't do, unless you activated the onclose.js add-on). This concludes the first draft of this guide (I'll add some stuff like the "Quiz" button soon) and I hope it helped. Your feedback is much appreciated.