More works by Ansgar Nierhoff in Public Spaces in Essen

Ein leichtes Spiel / An Easy Game, 1991
Spatial formation consisting of a forged steel polyhedron (Ø 134 cm), a forged steel stele 820 x 44,5 cm (H x Ø), a split steel round 6 x 798 cm (H x Ø), and a square steel grid base 12000 x 12000 cm
Location: Salzmarkt in the Essen city center approx 2100 m north-west of the Moltkeplatz. Coordinates: 51 27 23.63 N 7 00 34.71 E; (walking) route on OSM map here.

Zwei Kompositstreckungen berühren die Tangente an einen bodenbündigen Eisenkreis / Two composite extensions touch the tangent at a ground-flush iron circle,1993
Three-part sculpture in the north-western part of Essen’s city center next to the Limbecker Platz Shopping Center
Location: Friedrich-Ebert-Straße 2‒8 / corner of Limbecker Straße; approx 350 m to the north-west of the Salzmarkt. Coordinates: 51 27 30.0 N 7 00 25.76 E; (walking) route see OSM map here.
Pictures by Günter Pilger of the two works in the Essen city center here (scroll down on the page).
Within the 2010 LAB TV project in the year of the RUHR.2010 European Capital of Culture, Ansgar Nierhoff’s works Paarweise and Zwei Kompositstreckungen berühren die Tangente an einem bodenbündigen Eisenkreis were featured in the web video parody Paarweise ‒ ist es Kunst oder kann das wech / In Pairs ‒ is that art or can it go? The feature is avaiblable on YouTube here.
Impressions from an Exhibition and a Hiking Tour with Ansgar Nierhoff im August 2008 here.
Ansgar Nierhoff in the listing Kunst im öffentlichen Raum in Nordrhein-Westfalen / Art in Public Spaces in NRW.
Ansgar Nierhoff in Welt der Form (with a collection of fotos of his works).
Ansgar Nierhoff in (German) Wikipedia.
To the start page on Ansgar Nierhoff´s work at the Moltkeplatz here.