It could be made longer by changing
| penguin_id | species | island | bill_length_mm | bill_depth_mm |
| 1 | Adelie | Torgersen | 39.1 | 18.7 |
to
|penguin_id | species | island | attribute_name | measurement_value |
| 1 | Adelie | Torgersen | bill_length_mm | 39.1 |
| 1 | Adelie | Torgersen | bill_depth_mm | 18.7 |
I change data to make it “tidy” in the sense described at 12 Tidy data | R for Data Science but the penguins already is tidy. I’m not sure if “wide” and “long” are absolutes.