One of the hardest things in designing a pattern is to determine why and where to place the lead lines that will make your window possible to cut. In all actually, there is no right or wrong. It's all about aesthetics. That said, in most cases the trick is to minimize lead lines so your windows look less busy. Extra lead lines can be distracting. Below is a standard Cross Pattern that actually contains extra lines that are actually unnecessary. Those are lines which can easily be removed. The four lines radiating outward from the center of the cross to each corner of the window are inessential because the corner pieces can easily be cut without them. To me they only distract the eye and remove focus from the cross itself.
Lastly, I need to say extra lead lines may be added to make a statement or for stylized effect. In this case I believe that the first pattern we showed would be fine if you were using two alternating background colors. Believe it or not, I'd actually add more lines to achieve that effect so that the colors form a radiant pattern. Here are a few examples that help prove that there really is no right or wrong when it comes to lead lines. Sometimes you just want to be fancy (as in the bottom right). It's all a matter of preference.
Susan R is saying Merry Christmas in a big way with her oversized Candy Cane Lawn Ornament. She's maintained her curves and her straight lines on this and the soldering on her edge work was top notch! This will surely decorate her yard for years to come.
Linda L is taking a different approach to decorating her house for the Holidays with her Santa Head which appears to be looking into your house when mounted along the side of a window. She's made three of these and is only keeping one of them for herself so two people are going to be very happy when they receive their Santa Faces.
And here's what Santa looks like when he's 'installed'!
Annette made another JOY Suncatcher with Holly Leaves and Berries. She's used an iridised White glass for the letters and I think that this is possibly the best color scheme I've seen this done in yet. I think she said that she had another one under construction so I'll be looking forward to seeing what color Joy will be when we see it next.