OddThinking

Three painters surveyed an old wall.

The eldest painter said “Okay, we have been told to paint this wall white by Tuesday.

“Let’s buy enough white paint, clean the surface, and put masking tape down so we can do the edges cleanly.

“Then we will put on a coat of primer to ensure we get an even, long lasting finish.

“When it’s dry, we’ll put on the first coat of paint. When that’s dry, we’ll put on the second coat of paint. Should all be ready by Tuesday.”

The second painter scoffed, “I can’t believe you are still trying to use waterfall model! Haven’t you learnt anything about modern iterative techniques. We should use Rational Unified Painting.

“In the Inception Phase, we should address the highest risk. Does the customer really want white paint? We should build a prototype to test this. Let’s buy a small amount of white paint, and quickly slap it over the center of the wall. No need to paint near the edges; this is a disposable prototype, so the quality doesn’t matter. Then we will bring in the customer, and ask them to evaluate it. If they don’t like the look of it, then it’s lucky we didn’t do it the old way and waste all that time!

“Then, we can enter the elaboration phase. The highest risk by then will be whether we can still finish the job on time. We can address this risk by marking out 10% of the wall, and doing the full works on it – cleaning, marking, primer, and two coats. If we time how long it takes, and multiply it by ten, we will know if the job is achievable in time. Otherwise, we can stop immediately and cancel the project before we waste all that time! Lucky we aren’t doing it the old way.

“By marking out the rest of the wall in 10% chunks, we have an iteration plan for the construction phase, which we can re-evaluate at the end of every phase. No chance of this project heading in the wrong direction. Thank goodness for RUP!”

The third painter shook his head in disappointment. “What unnatural processes! Haven’t the experiences of the Chrysler Corporation taught you anything of the benefits of Extreme Painting?

“First we should bring in the customer to talk to us as we paint. We’ll soon learn the most important thing to the customer is to cover over the old flaking paint, so first we should put on a quick coat of pink paint I have left over from my last job. That way, if the customer cancels the job, at least there will be some benefit of the work we do, without the cost of buying paint. We will work in pairs, with one person painting. The other person’s job is to say ‘Hey, you missed a spot’, until its time to swap.

“The next most important requirement is that the wall be white, so we will buy enough white paint for one coat, and then we can simply repaint the wall with a coat of white. It doesn’t cost much to change the colour at this stage, especially if we keep checking the colour of the wall every time we dip the brush.

“The requirement that the finish be even and long-lasting is the lowest priority requirement, so we should do that last. There is no point planning ahead too much – the project might be cancelled, or the customer might change their mind. It’s best to get the important things done first.

“If it turns out the customer still wants a high-quality finish, we simply strip back all the work we have done, apply a primer, and paint it again. With the understanding we now have, and the testing regime in place, we should be able to achieve that in record time.

Finally, we can add the second layer of white paint, and the project will be finished, unless the customer has some more ideas in the meantime. There is no chance of this project not giving the customer something useful. Thank goodness for XP!”