# rock paper scissors ![](/static/mb/projects/a4-motion.png) ### ~avatar avatar ```sim input.onGesture(Gesture.Shake, () => { let img = Math.random(3) if (img == 0) { basic.showLeds(` # # # # # # . . . # # . . . # # . . . # # # # # # `) } else if (img == 1) { basic.showLeds(` . . . . . . # # # . . # # # . . # # # . . . . . . `) } else { basic.showLeds(` # # . . # # # . # . . . # . . # # . # . # # . . # `) } }) ``` In this project, you will build a Rock Paper Scissors game with the @boardname@. You can play the game with a friend who has it on a @boardname@. You can also play it with friends who are just using their hands. ### ~ ## Materials needed * Your @boardname@ -- that's it! ## Step 1: Getting started We want the @boardname@ to choose rock, paper, or scissors when you shake it. Try creating an ``on shake`` block so when you shake the @boardname@, it will run part of a program. ```blocks input.onGesture(Gesture.Shake, () => { }) ``` Next, when you shake the @boardname@, it should pick a random number from `0` to `2` and store it in the variable `weapon`. (This variable is named `weapon` because rock, paper, and scissors are the weapons you use to battle your friends!) Add a ``set`` block with a variable. Then add a ``pick random`` block, and store the random number in the variable, like this: ```blocks input.onGesture(Gesture.Shake, () => { let weapon = Math.random(3) }) ``` ### ~hint No one can predict random numbers. That's what makes them great for Rock Paper Scissors! ### ~ Each possible number these blocks can make (`0`, `1`, or `2`) means a different picture. We will show the right picture for that number on the LED screen. ## Step 2: Picking paper Put an ``if`` block after the ``let`` block that checks whether `weapon` is `0`. Make sure the ``if`` block has an ``else if`` part and an ``else`` part. Next, add a ``show leds`` block that shows a picture of a piece of paper: ```blocks input.onGesture(Gesture.Shake, () => { let weapon = Math.random(3) if (weapon == 0) { basic.showLeds(` # # # # # # . . . # # . . . # # . . . # # # # # # `) } else if (false) { } else { } }) ``` ## Step 3: A random rock Now we are going to add a new picture for the @boardname@ to show when another random number comes up. Make the ``else if`` part check if the variable `weapon` is `1`. Then add a ``show leds`` block with a picture of a rock. ```blocks input.onGesture(Gesture.Shake, () => { let weapon = Math.random(3) if (weapon == 0) { basic.showLeds(` # # # # # # . . . # # . . . # # . . . # # # # # # `) } else if (weapon == 1) { basic.showLeds(` . . . . . . # # # . . # # # . . # # # . . . . . . `) } else { } }) ``` ## Step 4: Suddenly scissors Add a ``show leds`` block with a picture of scissors to the ``else`` part: ```blocks input.onGesture(Gesture.Shake, () => { let weapon = Math.random(3) if (weapon == 0) { basic.showLeds(` # # # # # # . . . # # . . . # # . . . # # # # # # `) } else if (weapon == 1) { basic.showLeds(` . . . . . . # # # . . # # # . . # # # . . . . . . `) } else { basic.showLeds(` # # . . # # # . # . . . # . . # # . # . # # . . # `) } }) ``` ### ~hint You don't need to check if `weapon` is `2` because `2` is the only number left out of `0`, `1`, and `2`. That's why you can use an ``else`` instead of an ``else if``. ### ~ Your game is ready! Have fun! ## Step 5: Are you the greatest? Here is a way you can make your Rock Paper Scissors game better. When button ``A`` is pressed, the @boardname@ will add `1` to your score. Open the ``Game`` drawer, and then add the block ``change score by 1`` to your program, like this: ```blocks input.onButtonPressed(Button.A, () => { game.addScore(1) }) ``` ## Step 6: Prove you're the greatest! After your @boardname@ can add `1` to the score, show how many wins you have. ```blocks input.onButtonPressed(Button.A, () => { game.addScore(1) basic.showString("WINS:") basic.showNumber(game.score()) }) ``` ## Step 7: Staying honest Success! Your @boardname@ can track wins! But what about losses? Use the ``Game`` drawer to subtract `1` from your score when you press button `B`. Here are all the blocks you will need: ```shuffle input.onButtonPressed(Button.B, () => { game.addScore(-1) basic.showString("LOSSES:") basic.showNumber(game.score()) }) ``` ## Step 8: Hacking Rock Paper Scissors How else can you make your game better? Ever hear of [Rock Paper Scissors Spock Lizard](http://www.samkass.com/theories/RPSSL.html)?