I'd like to humbly point to what appears to be some misleading wording in exercise 17. Marching Penguins' instruction.
In the first paragraph of the instructions which reads:
Create a brand new Penguin class constructor starting in line 11. A penguin is an animal so it should also have the name and numLegs properties as well as a sayName method that prints the same thing as Animal's sayName method.
I'd humbly suggest for clarity that it read:
Create a brand new Penguin class constructor starting in line 11. A penguin is an animal so it should also have the name and numLegs properties. Also add an independent statement creating a sayName method similar to what is assigned to the Animal class.
Then referring to the second paragraph:
We're not done with animals yet, so we have still included the Animal constructor and its sayName method. The last two lines test your Penguin code.
With the intent of being helpful to fellow students in addition to having Codecademy's brand represented well, the first sentence's structure seems jumbled and the meaning is unclear. One can infer what is desired in the exercise by looking at the comments in the coding area however.