diff --git a/tikz/3d-gradient-colored/3d-gradient-colored.png b/tikz/3d-gradient-colored/3d-gradient-colored.png
index b3adbff..338f375 100644
Binary files a/tikz/3d-gradient-colored/3d-gradient-colored.png and b/tikz/3d-gradient-colored/3d-gradient-colored.png differ
diff --git a/tikz/3d-gradient-colored/3d-gradient-colored.tex b/tikz/3d-gradient-colored/3d-gradient-colored.tex
index 224666a..6116da0 100644
--- a/tikz/3d-gradient-colored/3d-gradient-colored.tex
+++ b/tikz/3d-gradient-colored/3d-gradient-colored.tex
@@ -3,7 +3,7 @@
 \usepackage[usenames,dvipsnames]{xcolor}
 \usepackage{pgfplots}
 \pgfplotsset{compat=1.11}
-\usepackage{tikz}
+\usetikzlibrary{arrows.meta}
 
 \begin{document}
 \pgfplotsset{
@@ -24,6 +24,10 @@
         domain=-2:2,
         view={0}{90},
         axis background/.style={fill=white},
+        xmin=-2, xmax=2,
+        ymin=-2, ymax=2,
+        axis equal image,
+        point meta rel=per plot
     ]
         \addplot3[surf,
                   samples=50,
@@ -35,13 +39,22 @@
         %           samples=30] 
         %         {x/exp(x^2+y^2)};
         \addplot3[blue,
+        point meta={
+            sqrt(
+                ((1-2*x^2)*exp(-x^2-y^2))^2+
+                (-2*x*y*exp(-x^2-y^2))^2
+            )        
+        },
                   quiver={
                           u={(1-2*x^2)*exp(-x^2-y^2)},
                           v={-2*x*y*exp(-x^2-y^2)},
                           scale arrows=0.3,
+                          every arrow/.append style={%
+                             -{Latex[scale length={max(0.01,\pgfplotspointmetatransformed/1000)}]},
+                             },
                          },
-                  -stealth,samples=15]
+                         samples=15]
                 {x/exp(x^2+y^2)};
     \end{axis}
 \end{tikzpicture}
-\end{document}
+\end{document}
\ No newline at end of file
diff --git a/tikz/3d-gradient-colored/3d-gradient-colored_contourtmp0.table b/tikz/3d-gradient-colored/3d-gradient-colored_contourtmp0.table
deleted file mode 100644
index a0cda11..0000000
--- a/tikz/3d-gradient-colored/3d-gradient-colored_contourtmp0.table
+++ /dev/null
@@ -1,341 +0,0 @@
-
-# Surface 0 of 1 surfaces
-
-# Curve title: ""3d-gradient-colored_contourtmp0.dat""
-# Contour 0, label:      0.4
- 0.62067  0.228107  0.4 
- 0.604191  0.20688  0.4 
- 0.550241  0.06895  0.4 
- 0.550241 -0.06898  0.4 
- 0.604214 -0.20691  0.4 
- 0.62067 -0.228102  0.4 
- 0.7586 -0.247438  0.4 
- 0.808601 -0.20691  0.4 
- 0.893435 -0.06898  0.4 
- 0.893435  0.06895  0.4 
- 0.808627  0.20688  0.4 
- 0.7586  0.247435  0.4 
- 0.62067  0.228107  0.4 
-
-
-# Contour 1, label:      0.3
- 0.48274  0.492135  0.3 
- 0.476086  0.48274  0.3 
- 0.402176  0.34481  0.3 
- 0.357394  0.20688  0.3 
- 0.34481  0.126098  0.3 
- 0.338757  0.06895  0.3 
- 0.338763 -0.06898  0.3 
- 0.34481 -0.126077  0.3 
- 0.357401 -0.20691  0.3 
- 0.402195 -0.34484  0.3 
- 0.476105 -0.48277  0.3 
- 0.48274 -0.49214  0.3 
- 0.62067 -0.583459  0.3 
- 0.7586 -0.59254  0.3 
- 0.89653 -0.537769  0.3 
- 0.9635 -0.48277  0.3 
- 1.03446 -0.405831  0.3 
- 1.07457 -0.34484  0.3 
- 1.13322 -0.20691  0.3 
- 1.16092 -0.06898  0.3 
- 1.16092  0.06895  0.3 
- 1.13323  0.20688  0.3 
- 1.07457  0.34481  0.3 
- 1.03446  0.405819  0.3 
- 0.963553  0.48274  0.3 
- 0.89653  0.537785  0.3 
- 0.7586  0.592536  0.3 
- 0.62067  0.583452  0.3 
- 0.48274  0.492135  0.3 
-
-
-# Contour 2, label:      0.2
- 0.48274  0.805972  0.2 
- 0.434239  0.7586  0.2 
- 0.34481  0.652343  0.2 
- 0.329248  0.62067  0.2 
- 0.276215  0.48274  0.2 
- 0.241422  0.34481  0.2 
- 0.220336  0.20688  0.2 
- 0.210381  0.06895  0.2 
- 0.210382 -0.06898  0.2 
- 0.220339 -0.20691  0.2 
- 0.241428 -0.34484  0.2 
- 0.27623 -0.48277  0.2 
- 0.329266 -0.6207  0.2 
- 0.34481 -0.652337  0.2 
- 0.434266 -0.75863  0.2 
- 0.48274 -0.805975  0.2 
- 0.62067 -0.865282  0.2 
- 0.7586 -0.87119  0.2 
- 0.89653 -0.835618  0.2 
- 1.03204 -0.75863  0.2 
- 1.03446 -0.757113  0.2 
- 1.17239 -0.627608  0.2 
- 1.17819 -0.6207  0.2 
- 1.27174 -0.48277  0.2 
- 1.31032 -0.399731  0.2 
- 1.33454 -0.34484  0.2 
- 1.37411 -0.20691  0.2 
- 1.39279 -0.06898  0.2 
- 1.39279  0.06895  0.2 
- 1.37412  0.20688  0.2 
- 1.33456  0.34481  0.2 
- 1.31032  0.399737  0.2 
- 1.27172  0.48274  0.2 
- 1.17825  0.62067  0.2 
- 1.17239  0.627653  0.2 
- 1.03446  0.757115  0.2 
- 1.03209  0.7586  0.2 
- 0.89653  0.835623  0.2 
- 0.7586  0.871183  0.2 
- 0.62067  0.865281  0.2 
- 0.48274  0.805972  0.2 
-
-
-# Contour 3, label:      0.1
- 0.62067  1.20274  0.1 
- 0.527412  1.17239  0.1 
- 0.48274  1.15931  0.1 
- 0.34481  1.05953  0.1 
- 0.326152  1.03446  0.1 
- 0.239045  0.89653  0.1 
- 0.20688  0.828226  0.1 
- 0.185143  0.7586  0.1 
- 0.152362  0.62067  0.1 
- 0.130273  0.48274  0.1 
- 0.115781  0.34481  0.1 
- 0.107  0.20688  0.1 
- 0.102853  0.06895  0.1 
- 0.102853 -0.06898  0.1 
- 0.107001 -0.20691  0.1 
- 0.115784 -0.34484  0.1 
- 0.130279 -0.48277  0.1 
- 0.152369 -0.6207  0.1 
- 0.185151 -0.75863  0.1 
- 0.20688 -0.828228  0.1 
- 0.239059 -0.89656  0.1 
- 0.326174 -1.03449  0.1 
- 0.34481 -1.05953  0.1 
- 0.48274 -1.15931  0.1 
- 0.527503 -1.17242  0.1 
- 0.62067 -1.20274  0.1 
- 0.7586 -1.20736  0.1 
- 0.89653 -1.17953  0.1 
- 0.914319 -1.17242  0.1 
- 1.03446 -1.12812  0.1 
- 1.17239 -1.04335  0.1 
- 1.18365 -1.03449  0.1 
- 1.31032 -0.926516  0.1 
- 1.33897 -0.89656  0.1 
- 1.44825 -0.758644  0.1 
- 1.53381 -0.6207  0.1 
- 1.58618 -0.497219  0.1 
- 1.59273 -0.48277  0.1 
- 1.6398 -0.34484  0.1 
- 1.66832 -0.20691  0.1 
- 1.68179 -0.06898  0.1 
- 1.68179  0.06895  0.1 
- 1.66832  0.20688  0.1 
- 1.63981  0.34481  0.1 
- 1.59275  0.48274  0.1 
- 1.58618  0.497228  0.1 
- 1.53383  0.62067  0.1 
- 1.44828  0.7586  0.1 
- 1.44825  0.75864  0.1 
- 1.33899  0.89653  0.1 
- 1.31032  0.92651  0.1 
- 1.18369  1.03446  0.1 
- 1.17239  1.04335  0.1 
- 1.03446  1.12813  0.1 
- 0.914383  1.17239  0.1 
- 0.89653  1.17953  0.1 
- 0.7586  1.20736  0.1 
- 0.62067  1.20274  0.1 
-
-
-# Contour 4, label:        0
- 4.89094e-08  1.99997  0 
--6.26617e-08  1.86204  0 
--1.1295e-07  1.72411  0 
- 1.42801e-08  1.58618  0 
- 1.04787e-07  1.44825  0 
- 3.47799e-07  1.31032  0 
- 5.77227e-08  1.17239  0 
--9.48916e-08  1.03446  0 
- 3.16071e-09  0.89653  0 
--1.18704e-07  0.7586  0 
- 1.03236e-07  0.62067  0 
- 5.89748e-08  0.48274  0 
--6.07234e-07  0.34481  0 
--3.00826e-07  0.20688  0 
- 5.76332e-08  0.06895  0 
--3.96564e-07 -0.06898  0 
--5.10344e-07 -0.20691  0 
- 7.21164e-08 -0.34484  0 
--6.73148e-08 -0.48277  0 
--4.38438e-08 -0.6207  0 
--2.8782e-08 -0.75863  0 
- 4.09067e-09 -0.89656  0 
--9.38127e-08 -1.03449  0 
--5.36999e-07 -1.17242  0 
--2.10373e-07 -1.31035  0 
- 1.06225e-07 -1.44828  0 
--4.81826e-07 -1.58621  0 
--1.30033e-08 -1.72414  0 
--6.11936e-08 -1.86207  0 
- 5.07091e-08 -2  0 
-
-
-# Contour 5, label:     -0.1
--0.89656  1.17953 -0.1 
--0.914403  1.17239 -0.1 
--1.03449  1.12813 -0.1 
--1.17242  1.04333 -0.1 
--1.1837  1.03446 -0.1 
--1.31035  0.926487 -0.1 
--1.339  0.89653 -0.1 
--1.44828  0.7586 -0.1 
--1.53382  0.62067 -0.1 
--1.58621  0.497151 -0.1 
--1.59274  0.48274 -0.1 
--1.6398  0.34481 -0.1 
--1.66832  0.20688 -0.1 
--1.68178  0.06895 -0.1 
--1.68178 -0.06898 -0.1 
--1.66831 -0.20691 -0.1 
--1.63979 -0.34484 -0.1 
--1.59273 -0.48277 -0.1 
--1.58621 -0.497159 -0.1 
--1.5338 -0.6207 -0.1 
--1.44828 -0.758597 -0.1 
--1.33896 -0.89656 -0.1 
--1.31035 -0.926474 -0.1 
--1.18365 -1.03449 -0.1 
--1.17242 -1.04332 -0.1 
--1.03449 -1.12811 -0.1 
--0.914331 -1.17242 -0.1 
--0.89656 -1.17953 -0.1 
--0.75863 -1.20736 -0.1 
--0.6207 -1.20275 -0.1 
--0.527497 -1.17242 -0.1 
--0.48277 -1.15932 -0.1 
--0.34484 -1.05956 -0.1 
--0.326174 -1.03449 -0.1 
--0.239061 -0.89656 -0.1 
--0.20691 -0.828301 -0.1 
--0.185154 -0.75863 -0.1 
--0.152369 -0.6207 -0.1 
--0.130278 -0.48277 -0.1 
--0.115783 -0.34484 -0.1 
--0.107 -0.20691 -0.1 
--0.102853 -0.06898 -0.1 
--0.102852  0.06895 -0.1 
--0.106999  0.20688 -0.1 
--0.115781  0.34481 -0.1 
--0.130274  0.48274 -0.1 
--0.152364  0.62067 -0.1 
--0.185147  0.7586 -0.1 
--0.20691  0.828304 -0.1 
--0.23904  0.89653 -0.1 
--0.326158  1.03446 -0.1 
--0.34484  1.05955 -0.1 
--0.48277  1.15932 -0.1 
--0.527396  1.17239 -0.1 
--0.6207  1.20275 -0.1 
--0.75863  1.20736 -0.1 
--0.89656  1.17953 -0.1 
-
-
-# Contour 6, label:     -0.2
--0.89656  0.83561 -0.2 
--1.03212  0.7586 -0.2 
--1.03449  0.757115 -0.2 
--1.17242  0.627578 -0.2 
--1.17822  0.62067 -0.2 
--1.27175  0.48274 -0.2 
--1.31035  0.3997 -0.2 
--1.33456  0.34481 -0.2 
--1.37413  0.20688 -0.2 
--1.3928  0.06895 -0.2 
--1.3928 -0.06898 -0.2 
--1.3741 -0.20691 -0.2 
--1.33452 -0.34484 -0.2 
--1.31035 -0.399632 -0.2 
--1.27172 -0.48277 -0.2 
--1.17822 -0.6207 -0.2 
--1.17242 -0.627606 -0.2 
--1.03449 -0.757113 -0.2 
--1.03207 -0.75863 -0.2 
--0.89656 -0.835615 -0.2 
--0.75863 -0.871188 -0.2 
--0.6207 -0.865294 -0.2 
--0.48277 -0.80599 -0.2 
--0.434266 -0.75863 -0.2 
--0.34484 -0.652396 -0.2 
--0.329265 -0.6207 -0.2 
--0.276228 -0.48277 -0.2 
--0.241423 -0.34484 -0.2 
--0.220334 -0.20691 -0.2 
--0.210379 -0.06898 -0.2 
--0.210377  0.06895 -0.2 
--0.220333  0.20688 -0.2 
--0.24142  0.34481 -0.2 
--0.276223  0.48274 -0.2 
--0.329258  0.62067 -0.2 
--0.34484  0.652384 -0.2 
--0.43424  0.7586 -0.2 
--0.48277  0.805988 -0.2 
--0.6207  0.86529 -0.2 
--0.75863  0.871183 -0.2 
--0.89656  0.83561 -0.2 
-
-
-# Contour 7, label:     -0.3
--0.89656  0.537758 -0.3 
--0.963546  0.48274 -0.3 
--1.03449  0.405778 -0.3 
--1.07456  0.34481 -0.3 
--1.13323  0.20688 -0.3 
--1.16092  0.06895 -0.3 
--1.16092 -0.06898 -0.3 
--1.13322 -0.20691 -0.3 
--1.07456 -0.34484 -0.3 
--1.03449 -0.405808 -0.3 
--0.963519 -0.48277 -0.3 
--0.89656 -0.537754 -0.3 
--0.75863 -0.592534 -0.3 
--0.6207 -0.58346 -0.3 
--0.48277 -0.492156 -0.3 
--0.476122 -0.48277 -0.3 
--0.402187 -0.34484 -0.3 
--0.357389 -0.20691 -0.3 
--0.34484 -0.126349 -0.3 
--0.338765 -0.06898 -0.3 
--0.338765  0.06895 -0.3 
--0.34484  0.126334 -0.3 
--0.357384  0.20688 -0.3 
--0.402179  0.34481 -0.3 
--0.476092  0.48274 -0.3 
--0.48277  0.49217 -0.3 
--0.6207  0.583472 -0.3 
--0.75863  0.592531 -0.3 
--0.89656  0.537758 -0.3 
-
-
-# Contour 8, label:     -0.4
--0.75863  0.247435 -0.4 
--0.808634  0.20688 -0.4 
--0.893406  0.06895 -0.4 
--0.893406 -0.06898 -0.4 
--0.808586 -0.20691 -0.4 
--0.75863 -0.247423 -0.4 
--0.6207 -0.228129 -0.4 
--0.604222 -0.20691 -0.4 
--0.550252 -0.06898 -0.4 
--0.550252  0.06895 -0.4 
--0.604208  0.20688 -0.4 
--0.6207  0.228119 -0.4 
--0.75863  0.247435 -0.4 
-
diff --git a/tikz/3d-gradient-colored/Makefile b/tikz/3d-gradient-colored/Makefile
index 4f4e340..3550670 100644
--- a/tikz/3d-gradient-colored/Makefile
+++ b/tikz/3d-gradient-colored/Makefile
@@ -8,7 +8,7 @@ make:
 	make clean
 
 clean:
-	rm -rf  $(TARGET) *.class *.html *.log *.aux *.data *.gnuplot *.script *.dat
+	rm -rf  $(TARGET) *.class *.html *.log *.aux *.data *.gnuplot *.script *.dat *.table
 
 gif:
 	pdfcrop $(SOURCE).pdf
diff --git a/tikz/3d-gradient-colored/README.md b/tikz/3d-gradient-colored/README.md
index 2b06571..75c008e 100644
--- a/tikz/3d-gradient-colored/README.md
+++ b/tikz/3d-gradient-colored/README.md
@@ -7,4 +7,11 @@ Creation
 --------
 * Make sure that `gnuplot` is installed and in your PATH.
 * You can let Wolfram|Alpha calculate you gradients (http://www.wolframalpha.com/input/?i=gradient+of+x%2F%28e%5E%28x%5E2%2By%5E2%29%29)
-* See http://en.wikibooks.org/wiki/LaTeX/Colors for colors
\ No newline at end of file
+* See http://en.wikibooks.org/wiki/LaTeX/Colors for colors
+
+
+Credits
+-------
+Jake helped me to remove the small white border at the left side which was
+caused by the arrows.
+See [Why does PGFplots plot more than the desired range in a 3D plot?](http://tex.stackexchange.com/a/227173/5645).
\ No newline at end of file