Again I was a bit confused by instructions and not sure whether the focus was on varying lines or mark making in general. I decided to do a bit of both on interpreted this exercise as trying out the variability of lines for making marks in different media.
Page 1: HB pencil
The first page was done in HB, trying to invent variations in line-based patterns by varying the characteristics of the line. I got into a flow of inventing different types of marks and ran out of spontaneous ideas after roughly half of the squares. Then I began to search more consciously for variation which added a systematic aspect to what I was doing.
When reflecting now, I seem to have taken one particular aspect of a drawing and varied this in the next, for example from short, straight lines to longer, curvy lines, or from flat gray lines to some with varying darkness.
Page 2: comparing different media
On the second page, I compared the effect of 5 different line-based patterns in 5 different media: 9B graphite pen, soft thin charcoal, grade 3 pressed charcoal block, 6B pencil, and 2B graphite block. I was surprised that differences were subtle at most, but then understood that I had used only two broad types of media, charcoal and graphite, with graphite being generally lighter than charcoal. Variation would therefore come rather from different movements and mark types, than from the difference between charcoal and graphite.