Creating a Block in Blockly

Thanks guys. I tried following your advice to not use blocking code, but ran into another problem. I can't change that value of variables inside the function prototype. For example, this code works:

setTimeout(function () {analogWrite(B14, 1.6 / 50.0, {freq:20});},1000);

setTimeout(function () {analogWrite(B14, 1.55 / 50.0, {freq:20});},2000);

setTimeout(function () {analogWrite(B14, 1.5 / 50.0, {freq:20});},3000);

setTimeout(function () {analogWrite(B14, 1.45 / 50.0, {freq:20});},4000);

But this code does not:

var pos = 1.6;
var posInc = 0.05;

setTimeout(function () {analogWrite(B14, pos / 50.0, {freq:20});},1000);
pos -= posInc;
setTimeout(function () {analogWrite(B14, pos / 50.0, {freq:20});},2000);
pos -= posInc;
setTimeout(function () {analogWrite(B14, pos / 50.0, {freq:20});},3000);
pos -= posInc;
setTimeout(function () {analogWrite(B14, pos / 50.0, {freq:20});},4000);

The result is that it moves to position 1.45 at time 1000. So I guess it has already run "pos -= posInc;" three times before it first calls the analogWrite() function.

Please help,
Rehman