<human>: How do you do this: How do you break a dogbane stalk open in order to access the core wood fiber?

OPTIONS:
- Lay the dogbane stalk out on a flat surface. Press your thumb into it to flatten it longitudinally. This will cause the stalk to break in half lengthwise.
- Lay the dogbane stalk out on a flat surface. Press your knee into it to flatten it longitudinally. This will cause the stalk to break in half lengthwise.
<bot>: Lay the dogbane stalk out on a flat surface. Press your thumb into it to flatten it longitudinally. This will cause the stalk to break in half lengthwise.