work with help from matty

Quaternions.jl

@@ -29,7 +29,7 @@ end
 
 function QuaternionMultiplication(l::Quaternion, r::Quaternion)
     R = [
-        r.r r.k r.j r.i
+        r.r r.k -r.j r.i
         -r.k r.r r.i r.j
         r.j -r.i r.r r.k
         -r.i -r.j -r.k r.r
@@ -45,7 +45,7 @@ Base.:*(l::Quaternion, r::Quaternion) =
 Base.iterate(q::Quaternion, state = 1) =
     state > 4 ? nothing : (collect(q)[state], state + 1)
 Base.length(q::Quaternion) = 4
-Base.collect(q::Quaternion) = [q.i q.j q.k q.r]
+Base.collect(q::Quaternion) = [q.i, q.j, q.k, q.r]
 Base.getindex(q::Quaternion, i) = collect(q)[i]
 Base.isapprox(a::Quaternion, b::Quaternion) = isapprox(collect(a), collect(b))