I presume you're thinking of starting in ARN because of the lower purchase price there
You have 20 segments, 4 in each of 4 continents and then 4 inter-continental flights - so that's appears OK. But:

• remember that though you can have 4 flight segments in your continent of orgin (EUR in your case) you can only have 2 stopovers. Perhaps you're thinking of transiting LHR and MAD?
• Your are required to finish you journey in the country of origin - ie back in Sweden, which means another segment