Trinity Stitch gone wacko

[Lollilulu]

Okay, I printed this pattern off the internet on how to do a trinity stitch and started out. Here's the pattern:

Multiple of 4 sts.
Row 1: (right side) purl across.
Row 2: * (k, p, k) all in next st, p3 tog rep from * across.
Row 3: purl across.
Row 4: * p3 tog, (k, p, k) all in next st; rep from * across.
Rep Rows 1-4 for pattern.

I cast on twelve and was happily knitting when I ran into a problem. There were only four stitches left on my needle. And it looked really weird. I was purling three together and never adding any! Does anyone have a better explanation of the trinity stitch that I could use?
Or what am I not seeing in this one?

[cam90066]

***(k, p, k) all in next st***

You're neglecting to do these increases. K the st but leave it on the left ndl, yarn fwd and P it (leave on left). Then bring yrn to back again and K it. NOW drop the st on left ndl. You've made 3 sts from 1.

cam

[Ingrid]

Another way is to k,yo,k into the one stitch. Knit, don't slide it off, bring the yarn to the front and knit it again. That will give you 3 total. Either way works.

[Lollilulu]

Thanks, y'all! I guess I wasn't reading it properly. I'll try the stitch again with the increases.