Aaaand finally I found this.
Legendary Homotin.
The almost unreadable text on the right hand side reads:
KAKSOIS-VALMET
THE SECRET WEAPON OF BRIGADE 70
Domestic tractors were light and had small engines. FDF's Transport Vehicle Depot joined two 2500 kg (2.5 metric tons) and 54 hp Valmet 500 tractors together with a hydraulic swiveled axle.
This twin-Valmet (conscripts called this "Homotin", "The Gay Maker") that had the mass of a forest work tractor but considerably higher combined engine power had an excellent terrain capability and pulling power. The downside was that the combination was hard to drive. Both tractors required a driver of their own and thus picking the right gear and timing the wheel turns mandated rules for finding drivers: identical twins who could read each other's minds.