diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..6a3417b
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1 @@
+/out/
diff --git a/out/production/HelloKotlin/AmsKt.class b/out/production/HelloKotlin/AmsKt.class
deleted file mode 100644
index 5971c78..0000000
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diff --git a/out/production/HelloKotlin/FortuneKt.class b/out/production/HelloKotlin/FortuneKt.class
deleted file mode 100644
index c4d1987..0000000
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diff --git a/out/production/HelloKotlin/META-INF/HelloKotlin.kotlin_module b/out/production/HelloKotlin/META-INF/HelloKotlin.kotlin_module
deleted file mode 100644
index 826e881..0000000
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diff --git a/out/production/HelloKotlin/WhatToDoTodayKt.class b/out/production/HelloKotlin/WhatToDoTodayKt.class
deleted file mode 100644
index f8177ba..0000000
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diff --git a/src/aquarium/Aquarium.kt b/src/aquarium/Aquarium.kt
new file mode 100644
index 0000000..e65e4ab
--- /dev/null
+++ b/src/aquarium/Aquarium.kt
@@ -0,0 +1,19 @@
+package aquarium
+
+class Aquarium(var length: Int = 100, var width: Int = 20, var height: Int = 40) {
+
+    var volume: Int
+        get() = width * height * length / 1000
+        set(value) {
+            height = (value * 1000) / (width * length)
+        }
+
+    var water = volume * 0.9
+
+    constructor(numberOfFish: Int): this() {
+        val water = numberOfFish * 2000 // cm3
+        val tank = water + water * 0.1
+        height = (tank / (length * width)).toInt()
+    }
+
+}
\ No newline at end of file
diff --git a/src/aquarium/main.kt b/src/aquarium/main.kt
new file mode 100644
index 0000000..47a880f
--- /dev/null
+++ b/src/aquarium/main.kt
@@ -0,0 +1,32 @@
+package aquarium
+
+fun main(args: Array<String>) {
+    buildAquarium()
+}
+
+private fun buildAquarium() {
+    val myAquarium = Aquarium()
+
+    println(
+        "Length: ${myAquarium.length}" +
+        "Width: ${myAquarium.width}" +
+        "Height: ${myAquarium.height}"
+    )
+
+    myAquarium.height = 80
+
+    println("Height: ${myAquarium.height} cm")
+
+    println("Volume: ${myAquarium.volume} liters")
+
+    val smallAquarium = Aquarium(length=20, width=15, height=30)
+    println("Small Aquarium Volume: ${smallAquarium.volume} liters")
+
+    val myAquarium2 = Aquarium(numberOfFish = 9)
+    println(
+        "Aquarium 2: ${myAquarium2.volume} liters with " +
+        "length ${myAquarium2.length}" +
+        "width: ${myAquarium2.width}" +
+        "height: ${myAquarium2.height}"
+    )
+}