Try to change (again) the travis file. May work this time?

.travis.yml

@@ -1,17 +1,13 @@
-dist: bionic
 language: c
 
 addons:
   apt:
     packages:
       - lcov
-
+      - imagemagick
-os:
+  homebrew:
-  - linux
+    packages:
-  - osx
+      - imagemagick
-compiler:
-  - clang
-  - gcc
 
 script:
   - mkdir build
@@ -22,14 +18,59 @@ script:
   - cd tests
   - ./testMyRays
 
-addons:
+before_install:
-  homebrew:
+  - if [[ "$TRAVIS_OS_NAME" == "osx" ]]; then brew unlink python@2 ; fi
-    packages:
+  - if [[ "$TRAVIS_OS_NAME" == "osx" ]]; then brew install imagemagick ; fi
-    - imagemagick
-    update: true
 
 jobs:
   include:
+    - os: linux
+      dist: bionic
+      arch: amd64
+      compiler: gcc
+
+    - os: linux
+      dist: bionic
+      arch: amd64
+      compiler: clang
+
+    - os: linux
+      dist: focal
+      arch: amd64
+      compiler: gcc
+
+    - os: linux
+      dist: focal
+      arch: amd64
+      compiler: clang
+
+
+    - os: osx
+      compiler: clang
+      osx_image: xcode12.2
+
+    - os: linux
+      dist: focal
+      arch: arm64
+      compiler: gcc
+
+    - os: linux
+      dist: bionic
+      arch: arm64
+      compiler: gcc
+
+    - os: osx
+      compiler: clang
+      osx_image: xcode10.3
+
+    - os: osx
+      compiler: clang
+      osx_image: xcode11.6
+
+    - os: osx
+      compiler: clang
+      osx_image: xcode12
+
     - stage: "Coverage"
       os: linux
       compiler: gcc
@@ -41,3 +82,16 @@ jobs:
         - cmake --build . --target coveralls
       after_success:
         - bash <(curl -s https://codecov.io/bash)
+
+  allow_failures:
+    - os: linux
+      arch: arm64
+
+    - os: osx
+      osx_image: xcode10.3
+
+    - os: osx
+      osx_image: xcode11.6
+
+    - os: osx
+      osx_image: xcode12