diff --git a/src/GooseFEM/Dynamics.cpp b/src/GooseFEM/Dynamics.cpp
index 6f039b7..b25555c 100644
--- a/src/GooseFEM/Dynamics.cpp
+++ b/src/GooseFEM/Dynamics.cpp
@@ -1,90 +1,90 @@
 /* =================================================================================================
 
 (c - GPLv3) T.W.J. de Geus (Tom) | tom@geus.me | www.geus.me | github.com/tdegeus/GooseFEM
 
 ================================================================================================= */
 
 #ifndef GOOSEFEM_DYNAMCS_CPP
 #define GOOSEFEM_DYNAMCS_CPP
 
 // -------------------------------------------------------------------------------------------------
 
 #include "Dynamics.h"
 
 // ======================================= GooseFEM::Dynamics =======================================
 
 namespace GooseFEM {
 namespace Dynamics {
 
 // -------------------------------------------------------------------------------------------------
 
 inline void velocityVerlet(Geometry &g, double dt)
 {
   // local variables and history
   ColD V;
   ColD A;
   ColD V_n = g.dofs_v();
   ColD A_n = g.dofs_a();
 
   // (1) new positions
-  g.set_x( g.x() + dt * g.v() + 0.5 * std::pow(dt,2.) * g.a() );
+  g.set_u( g.u() + dt * g.v() + 0.5 * std::pow(dt,2.) * g.a() );
 
   // (2a) estimate new velocity
   // - new velocity
   V = V_n + dt * A_n;
   // - update particles
   g.set_v(V);
   // - solve for accelerations
   A = g.solve();
   // - new velocity
   V = V_n + .5 * dt * ( A_n + A );
   // - update particles
   g.set_v(V);
 
   // (2b) new velocity
   // - solve for accelerations
   A = g.solve();
   // - new velocity
   V = V_n + .5 * dt * ( A_n + A );
   // - update particles
   g.set_v(V);
 
   // (3) new accelerations
   // - solve for accelerations
   A = g.solve();
   // - update particles
   g.set_a(A);
 
   // process time-step
   g.timestep(dt);
 }
 
 // -------------------------------------------------------------------------------------------------
 
 inline size_t quasiStaticVelocityVerlet(Geometry &g, double dt, double tol)
 {
   // reset residuals
   g.reset();
 
   // zero-initialize iteration counter
   size_t iiter = 0;
 
   // loop until convergence
   while ( true )
   {
     // - update iteration counter
     iiter++;
     // - time-step
     velocityVerlet(g,dt);
     // - check for convergence
     if ( g.stop(tol) ) return iiter;
   }
 }
 
 // -------------------------------------------------------------------------------------------------
 
 }} // namespace ...
 
 // =================================================================================================
 
 #endif
diff --git a/src/GooseFEM/Dynamics.h b/src/GooseFEM/Dynamics.h
index 34836ca..c8c9a1a 100644
--- a/src/GooseFEM/Dynamics.h
+++ b/src/GooseFEM/Dynamics.h
@@ -1,67 +1,67 @@
 /* =================================================================================================
 
 (c - GPLv3) T.W.J. de Geus (Tom) | tom@geus.me | www.geus.me | github.com/tdegeus/GooseFEM
 
 ================================================================================================= */
 
 #ifndef GOOSEFEM_DYNAMICS_H
 #define GOOSEFEM_DYNAMICS_H
 
 // -------------------------------------------------------------------------------------------------
 
 #include "GooseFEM.h"
 
 // ======================================= GooseFEM::Dynamics =======================================
 
 namespace GooseFEM {
 namespace Dynamics {
 
 // -------------------------------------------------------------------------------------------------
 
 class Geometry
 {
 public:
 
   // solve for DOF-accelerations [ndof]
   virtual ColD solve() const { return ColD(); };
 
   // reset residuals, check for convergence
   virtual void reset()          { return;       }
   virtual bool stop(double tol) { UNUSED(tol); return false; };
 
   // process time-step
   virtual void timestep(double dt) { UNUSED(dt); return; };
 
   // return nodal vectors [nnode, ndim]
-  virtual MatD x() const { return MatD(); };
+  virtual MatD u() const { return MatD(); };
   virtual MatD v() const { return MatD(); };
   virtual MatD a() const { return MatD(); };
 
   // return DOF values [ndof]
   virtual ColD dofs_v() const { return ColD(); };
   virtual ColD dofs_a() const { return ColD(); };
 
   // overwrite nodal vectors [nnode, ndim]
-  virtual void set_x(const MatD &pvector) { UNUSED(pvector); return; };
+  virtual void set_u(const MatD &nodevec) { UNUSED(nodevec); return; };
 
   // overwrite nodal vectors, reconstructed from DOF values [ndof]
   virtual void set_v(const ColD &dofval) { UNUSED(dofval); return; };
   virtual void set_a(const ColD &dofval) { UNUSED(dofval); return; };
 
 };
 
 // -------------------------------------------------------------------------------------------------
 
 // evaluate one time step
 inline void velocityVerlet(Geometry &geometry, double dt);
 
 // iterate until all nodes have come to a rest
 inline size_t quasiStaticVelocityVerlet(Geometry &geometry, double dt, double tol);
 
 // -------------------------------------------------------------------------------------------------
 
 }} // namespace ...
 
 // =================================================================================================
 
 #endif