Why would they give someone who "have no idea about programming" that assignment? Or is it just you who've been skipping courses?

You'll want to do a search for "picking" or alternatively use a button library and turn your shape into a button.  When the item is picked, adjust it's placement on the screen using mouseX & mouseY.  There are many examples available of this type of task.  Check out http://openprocessing.org

You may have a look at the "Getting Started with Processing" book and the corresponding examples (especially chapter 5, starting with example 12) that you can find in the Processing Development Environment, menu File > Examples.

Thx a lot for the replies ppl. I will check all the options. I have the book about processing but never got that far.

@bjordal: Well, no, I'm not skipping courses. I am studying Game Design and Analysis and the teacher thought it would be best for us brainstormers to get our hands dirty with some coding, just to see how it feels. That is all nice and good, but not possible in my opinion, because programming is not exactly an everyday occurrence in the life of a user/gamer. It takes time, dedication and a very specific mindset which is totally different from the mindset of people who design with artistry in mind. In any case, the teacher insisted that it would be good, so here I am.

Anyway, thx all.

All right, in addition to your Tangram shapes, here is the rest. Picking, moving by left-clicking and rotating by right-clicking.

There are even a few nifty little nuggets in there like keeping all shapes on the screen and forcing 45 degrees angles.

You will need the Picking library for Processing, which you can download here.

Of course, you could very well use object-oriented programming here, but in this case I just used a few arrays.

1. // requires Picking library for Processing
2. // http://code.google.com/p/processing-picking-library/
   
3. 
   
4. import picking.*;
5. Picker picker;
6. 
   
7. int id;
8. int number = 30;
9. 
   
10. float[] xpos = new float[number];
11. float[] ypos = new float[number];
12. color[] colors = new color[number];
13. int[] rotation = new int[number];
14. 
    
15. void setup() {
16.   size(800, 800);
17.   smooth();
18.   noStroke();
19.   picker = new Picker(this);
20.   initScene();
21. }
22. 
    
23. void draw() {
24.   background(255);
25. 
    
26.   // make pickers & shapes
27.   for (int i=0; i<number; i++) {
28.     pushMatrix();
29.     picker.start(i);
30.     translate(xpos[i],ypos[i]);
31.     rotate(radians(rotation[i]));
32.     rectMode(CENTER);
33.     fill(colors[i]);
34.     rect(0,0,100,100);
35.     popMatrix();
36.   }
37.   picker.stop();
38. 
    
39.   if (mousePressed) {} // make sure the picked object doesn't change while dragging
40.   else {
41.     if (mouseY > 0 && mouseY <height) { // prevent ArrayIndexOutOfBoundsException-bug in picker library
42.       id = picker.get(mouseX, mouseY);
43.     }
44.   }
45. }
46. 
    
47. void keyPressed() {
48.   if (key == 'b') { for (int i=0; i<number; i++) { colors[i] = color(0); } }
49.   if (key == 'c') { for (int i=0; i<number; i++) { colors[i] = color(random(255),random(255),random(255)); } }
50.   if (key == ' ') { initScene(); }
51. }
52. 
    
53. void mouseDragged() {
54.   if (id != -1) {
55.     // movement
56.     if (mouseButton == LEFT) {
57.       float xDif = xpos[id] - mouseX;
58.       float yDif = ypos[id] - mouseY;
59.       float xMov = mouseX - pmouseX;
60.       float yMov = mouseY - pmouseY;
61.       xpos[id] = mouseX + xDif + xMov;
62.       ypos[id] = mouseY + yDif + yMov;
63.     }
64.     // rotation
65.     if (mouseButton == RIGHT) {
66.       int xMov = mouseX - pmouseX;
67.       rotation[id] = rotation[id] + xMov;
68.     }
69.   }
70. }
71. 
    
72. void mouseReleased() {
73.   if (id != -1) {
74.     // force 45 degree angles
75.     rotation[id] = round(rotation[id]/45.0)*45;
76.     // make sure nothing goes off-screen
77.     xpos[id] = constrain(xpos[id],0,width);
78.     ypos[id] = constrain(ypos[id],0,height);
79.   }
80. }
81. 
    
82. void initScene() {
83.   for (int i=0; i<number; i++) {
84.     xpos[i] = random(width);
85.     ypos[i] = random(height);
86.     colors[i] = color(random(255),random(255),random(255));
87.     rotation[i] = int(random(360));
88.     rotation[i] = round(rotation[i]/45.0)*45;
89.   }
90. }

Good luck with the remaining steps!

..a very specific mindset which is totally different from the mindset of people who design with artistry in mind.

Lets agree to disagree on that.

For the sake of discussion, I think your teacher has a good idea, but pushing your in the water without teaching how to swim might not be the best way...
I believe an artist, particularly those delegating technical details to others, must have at least some base knowledge of the technique: a music composer must have at least base knowledge of a musical instrument to write music that can be played on it, a designer must know what can be cast industrially with a kind of plastic to make proper objects, etc.
So a base knowledge of programming is useful for a computer game designer. But a step by step teaching of the bases seems more appropriate here.

You haven't took the easiest task, I fear..

@amnon.owed : Thx a lot man, I will try that. I will also look Game Maker 8. A co-student advised me to check that and see what I can come up with.

@bjordal : Agreed

@phi.iho : True. I also explained that to the teacher but he was confident that we could complete the task.