1. void keyPressed() {
   
2. inputByUser = inputByUser + key;
3. }

with inputByUser being a global var (defined before setup)

1. String inputByUser = "aaaaaggagaggagagagactcaagcacgcccctcacaggactgct" + "gaggccctgcaggtgtctgcagcatgtgcccaggccggggactctgtaagccactgctggagaccac"+
2. "tcccatcctttctcccatttctctagacctgctgcctatacagtcactttttttttttttttgagacggagtc"+"tcgctctgtcgcccaggctggagtgcagtggcgggatctcggctcactgcaacgtccgcctcccgggttcacgccattctcctgcctcagcctcccaagtagctggga"
3. + "ccacagcgcccgccactacgcccggctaattttttgtatttttagtagagacggggtttcaccgttttagccgggatggtctcgatctcctgacctcgtgatccgcccgcctcggcctcccaaagtgctgggattacaggcgtgatacagtcacttttatgtggtttcgccaattttattccagctctgaaattctctgagctccccttacaagcagaggtgagctaagggctggagctcaagccattcaaccccctaccagatctgacgaatgtgatggccacatcccggaaatatgaagacctg";
4. 
   
5. int j;
6. 
   
7. void setup () {
8.   size(600, 600);
9.   background(111);
10. }
11. void draw () {
12.   background(111);
13.   for (int i = 0; i < inputByUser.length() ; i++) {
14.     text(inputByUser, 22, i*17+j);
15.   }
16.   j++;
17. }

1. String inputByUser = "aaaaaggagaggagagagactcaagcacgcccctcacaggactgct" +
2. "gaggccctgcaggtgtctgcagcatgtgcccaggccggggactctgtaagccactgctggagaccac"+
3. "tcccatcctttctcccatttctctagacctgctgcctatacagtcactttttttttttttttgagacggagtc"+
4. "tcgctctgtcgcccaggctggagtgcagtggcgggatctcggctcactgcaacgtccgcctcccgggttcacgccattctcctgcctcagcctcccaagtagctggga"
5. + "ccacagcgcccgccactacgcccggctaattttttgtatttttagtagagacggggtttcaccgttttagccgggatggtctcgatctcctgacctcgtgatccgcccgcctcggcctcccaaagtgctgggattacaggcgtgatacagtcacttttatgtggtttcgccaattttattccagctctgaaattctctgagctccccttacaagcagaggtgagctaagggctggagctcaagccattcaaccccctaccagatctgacgaatgtgatggccacatcccggaaatatgaagacctg";
6. int i=0;
7. float j=0;
8. void setup () {
9.   size(600, 600);
10.   background(111);
11.   frameRate(8);
12. }
13. void draw () {
14.   background(111);
15.   // rotate(j);
16.   j+=.01;
17.   //text(inputByUser.charAt(i), 22, i*17+j);
18.   doSymbol (inputByUser.charAt(i));
19.   i++;
20.   if (i > inputByUser.length()) i=0;
21. }
22. void doSymbol(char a) {
23.   println (a);
24.   switch (a) {
25.   case 'c':
26.     fill(255, 2, 2);
27.     doRect();
28.     break;
29.   case 'a':
30.     fill(2, 2, 255);
31.     doRect();
32.     break; 
33.   case 'g':
34.     fill(2, 254, 255);
35.     doRect();
36.     break; 
37.   case 't':
38.     fill(2, 255, 255);
39.     doRect();
40.     break;   
41.   default:
42.     fill(255, 2, 255);
43.     doRect();
44.     break;
45.   }
46. }
47. void doRect() {
48.   rect (100, 100, width-200, height-200);
49. }
50. //
51. Greetings, Chrisir

1. String inputByUser = "aaaaaggagaggagagagactcaagcacgcccctcacaggactgct" +
2. "gaggccctgcaggtgtctgcagcatgtgcccaggccggggactctgtaagccactgctggagaccac"+
3. "tcccatcctttctcccatttctctagacctgctgcctatacagtcactttttttttttttttgagacggagtc"+
4. "tcgctctgtcgcccaggctggagtgcagtggcgggatctcggctcactgcaacgtccgcctcccgggttcacgccattctcctgcctcagcctcccaagtagctggga"
5. + "ccacagcgcccgccactacgcccggctaattttttgtatttttagtagagacggggtttcaccgttttagccgggatggtctcgatctcctgacctcgtgatccgccc"+
6. "gcctcggcctcccaaagtgctgggattacaggcgtgatacagtcacttttatgtggtttcgccaattttattccagctctgaaattctctgagctccccttacaagcagaggt"+
7. "gagctaagggctggagctcaagccattcaaccccctaccagatctgacgaatgtgatggccacatcccggaaatatgaagacctg";
8. //
9. int i=0;    // your pos within the string
10. float j=0;  // angle
11. //
12. void setup () {
13.   size(600, 600);
14.   background(111);
15.   frameRate(8);
16. }
17. //
18. void draw () {
19.   background(111);
20.   translate (width/2, height/2);
21.   rotate(j);
22.   j+=.01;
23.   //text(inputByUser.charAt(i), 22, i*17+j);
24.   doSymbol (inputByUser.charAt(i));
25.   i++;
26.   if (i > inputByUser.length()) i=0;
27. }
28. //
29. void doSymbol(char a) {
30.   println (a);
31.   switch (a) {
32.   case 'c':
33.     fill(255, 2, 2);
34.     doRect();
35.     break;
36.   case 'a':
37.     fill(2, 2, 255);
38.     // doRect();
39.     ellipse(0, 0, 200, 100);
40.     break;
41.   case 'g':
42.     fill(2, 254, 255);
43.     // doRect();
44.     triangle(-100, -100,
45.     0, 100,
46.     100, -100);
47.     break;
48.   case 't':
49.     fill(2, 255, 255);
50.     doRect();
51.     break;  
52.   default:
53.     fill(255, 255, 255);
54.     doRect();
55.     break;
56.   }
57. }
58. //
59. void doRect() {
60.   rect (-100, -100, 200, 200);
61. }
62. //