Python 3, 47 bytes
f=lambda l,i=3:i+1and abs(l[i]-l[i-1])-f(l,i-1)
Take complex number input. Outputs as Truthy/Falsey swapped. Test cases [from Noodle9][1]from Noodle9.
48 bytes
lambda a,b,c,d:A(a-b)+A(c-d)-A(b-c)-A(d-a)
A=abs
Python 3, 47 bytes
f=lambda l,i=3:i+1and abs(l[i]-l[i-1])-f(l,i-1)
Take complex number input. Outputs as Truthy/Falsey swapped. Test cases [from Noodle9][1].
48 bytes
lambda a,b,c,d:A(a-b)+A(c-d)-A(b-c)-A(d-a)
A=abs
Python 3, 47 bytes
f=lambda l,i=3:i+1and abs(l[i]-l[i-1])-f(l,i-1)
Take complex number input. Outputs as Truthy/Falsey swapped. Test cases from Noodle9.
48 bytes
lambda a,b,c,d:A(a-b)+A(c-d)-A(b-c)-A(d-a)
A=abs
Python 3, 4847 bytes
f=lambda l,i=3:i+1and abs(l[i]-l[i-1])-f(l,i-1)
Take complex number input. Outputs as Truthy/Falsey swapped. Test cases [from Noodle9][1].
48 bytes
lambda a,b,c,d:A(a-b)+A(c-d)-A(b-c)-A(d-a)
A=abs
Take complex number input. Outputs as Truthy/Falsey swapped. Test cases from Noodle9 .
Python, 48 bytes
lambda a,b,c,d:A(a-b)+A(c-d)-A(b-c)-A(d-a)
A=abs
Take complex number input. Outputs as Truthy/Falsey swapped. Test cases from Noodle9 .
Python 3, 47 bytes
f=lambda l,i=3:i+1and abs(l[i]-l[i-1])-f(l,i-1)
Take complex number input. Outputs as Truthy/Falsey swapped. Test cases [from Noodle9][1].
48 bytes
lambda a,b,c,d:A(a-b)+A(c-d)-A(b-c)-A(d-a)
A=abs
Python, 48 bytes
lambda a,b,c,d:A(a-b)+A(c-d)-A(b-c)-A(d-a)
A=abs
Take complex number input. Outputs as Truthy/Falsey swapped. Test cases from Noodle9.