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docs/lessons/night-light/offset-image/activity.md

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+# offset image challenges
+
+Coding challenges for the offset image tutorial. #docs
+
+## Before we get started
+
+Complete the following exercise. Your code should look like this:
+
+```blocks
+offset = 0
+basic.forever(() => {
+    if (offset == -4) {
+        basic.showString("Push button A", 150)
+    }
+    images.createImage(`
+. . # . .
+. . # . .
+. . # . .
+. # # # .
+. . # . .
+`).showImage(offset)
+})
+input.onButtonPressed(Button.A, () => {
+    offset = offset + 1
+})
+```
+
+### Challenge 1
+
+Create a condition for if button `B` is pressed. We want the image to move to the left when button `B` is pressed.
+
+```
+offset = 0
+basic.forever(() => {
+    if (offset == -4) {
+        basic.showString("Push button A", 150)
+    }
+    images.createImage(`
+. . # . .
+. . # . .
+. . # . .
+. # # # .
+. . # . .
+`).showImage(offset)
+})
+input.onButtonPressed(Button.A, () => {
+    offset = offset + 1
+})
+input.onButtonPressed(Button.B, () => {
+    offset = offset - 1 // ***
+}) // ***
+```
+
+* Run the code to see if it works as expected.
+
+### Challenge 2
+
+### @video td/videos/offset-image-2
+
+Now we want to make sure that the button does not go off the screen to the right. Add a new line that checks to see if offset = 5 after button `A` is pressed.
+
+If `offset = 5` then prompt the user to move the image to the left by displaying the text: "Push button B".
+
+```
+offset = 0
+basic.forever(() => {
+    if (offset == -4) {
+        basic.showString("Push button A", 150)
+    }
+    if (offset == 5) {
+        basic.showString("Press Button B", 150) // ***
+    }
+    images.createImage(`
+. . # . .
+. . # . .
+. . # . .
+. # # # .
+. . # . .
+`).showImage(offset)
+})
+input.onButtonPressed(Button.A, () => {
+    offset = offset + 1
+})
+input.onButtonPressed(Button.B, () => {
+    offset = offset - 1
+})
+```
+
+* Run the code to see if it works as expected.
+
+**Challenge 3**
+
+Now make sure the image does not go off the left side and if it does, prompt the user to push button `A`.
+