diff --git a/ob-asymptote.el b/ob-asymptote.el
index de99ca3..a088fab 100644
--- a/ob-asymptote.el
+++ b/ob-asymptote.el
@@ -61,20 +61,19 @@ This function is called by `org-babel-execute-src-block'."
                      "pdf"))
          (cmdline (cdr (assq :cmdline params)))
          (in-file (org-babel-temp-file "asymptote-"))
-         (cmd
-	  (concat "asy "
-		  (if out-file
-		      (concat
-		       "-globalwrite -f " format
-		       " -o " (org-babel-process-file-name out-file))
-		    "-V")
-		  " " cmdline
-		  " " (org-babel-process-file-name in-file))))
+         (cmd `("asy"
+                ,@(if out-file
+                      `("-globalwrite" "-f" format
+                        "-o" (org-babel-process-file-name out-file))
+                    "-V")
+                cmdline
+                (org-babel-process-file-name in-file))))
     (with-temp-file in-file
       (insert (org-babel-expand-body:generic
-	       body params
-	       (org-babel-variable-assignments:asymptote params))))
-    (message cmd) (shell-command cmd)
+               body params
+               (org-babel-variable-assignments:asymptote params))))
+    (message (mapconcat #'shell-quote-argument cmd " "))
+    (apply #'call-process "asy" nil nil cmd) ;should "asy" be a user option?
     nil)) ;; signal that output has already been written to file
 
 (defun org-babel-prep-session:asymptote (_session _params)