diff --git a/imgs/tutorial.png b/imgs/tutorial.png
new file mode 100644
index 0000000..c8eaf45
Binary files /dev/null and b/imgs/tutorial.png differ
diff --git a/main.js b/main.js
index 3c27318..d933b73 100644
--- a/main.js
+++ b/main.js
@@ -1,5 +1,9 @@
 import { Resistor, SeriesResistor, ParallelResistor } from './modules/resistors.js';
 
+window.Resistor = Resistor
+window.SeriesResistor = SeriesResistor
+window.ParallelResistor = ParallelResistor
+
 var resistorValues = [100, 1000]
 var N = 4
 var maxValue = Math.max(...resistorValues)
@@ -41,6 +45,7 @@ console.log(`Parameters: N = ${N}, values = ${resistorValues} `);
 for (i = 0; i < N; i++)
     bottomUpDP();
 console.log("Finished computation of DP array");
+window.numberline = numberline
 
 function missings() {
     var missing = new Set()
@@ -52,6 +57,3 @@ function missings() {
 }
 console.log(`We found a composite resistor for every value in the range [1, ${N * maxValue + 1}] but for: ${[...missings()].join(",")}`)
 
-numberline[420].draw() // Draw the Resistor diagram for 420 Ohm as SVG
-
-console.log(numberline)
diff --git a/modules/resistors.js b/modules/resistors.js
index c7ff7be..69a0cdb 100644
--- a/modules/resistors.js
+++ b/modules/resistors.js
@@ -35,7 +35,7 @@ class Resistor {
         var [width, height] = [50, 100]
         return [svg, width, height]
     }
-    draw() {
+    draw(element = document.getElementsByTagName("body")[0]) {
         var [svg, width, height] = this.getSVG();
         var maxHeight = height + 2*25
         var maxWidth = width
@@ -47,7 +47,7 @@ class Resistor {
             ${svg}
             </g>
             </svg>`
-        document.getElementsByTagName("body")[0].innerHTML = thesvg;
+        element.innerHTML += thesvg;
     }
 }