Update README.md

README.md

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 |[![Build Status](https://travis-ci.org/yuanming-hu/taichi.svg?branch=master)](https://travis-ci.org/yuanming-hu/taichi)|[![Build Status](https://ci.appveyor.com/api/projects/status/github/yuanming-hu/taichi?branch=master&svg=true)](https://ci.appveyor.com/project/IteratorAdvance/taichi)|[![Documentation Status](https://readthedocs.org/projects/taichi/badge/?version=latest)](http://taichi.readthedocs.io/en/latest/?badge=latest)|[![Join the chat at https://gitter.im/taichi-dev/Lobby](https://badges.gitter.im/taichi-dev/Lobby.svg)](https://gitter.im/taichi-dev/Lobby?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge&utm_content=badge)|
 
 ## News
+ - May 17, 2019: [Giga-Voxel SPGrid Topology Optimization Solver](https://github.com/yuanming-hu/spgrid_topo_opt) is released!
  - March 4, 2019: [MLS-MPM/CPIC solver](https://github.com/yuanming-hu/taichi_mpm) is now MIT-licensed!
  - August 14, 2018: [MLS-MPM/CPIC solver](https://github.com/yuanming-hu/taichi_mpm) reloaded! We made it closed-source for a while, which is required by anonymous peer review. It delivers 4-14x performance boost over the previous state of the art on CPUs.
 
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+<img src="https://github.com/yuanming-hu/public_files/raw/master/graphics/topopt/bird-beak.gif">
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  <img src="https://github.com/yuanming-hu/public_files/raw/master/graphics/mls-mpm-cpic/water_wheel.gif"> <img src="https://github.com/yuanming-hu/public_files/raw/master/graphics/mls-mpm-cpic/sand_paddles.gif">
 <img src="https://github.com/yuanming-hu/public_files/raw/master/graphics/mls-mpm-cpic/armodillo.gif" style=""> <img src="https://github.com/yuanming-hu/public_files/raw/master/graphics/mls-mpm-cpic/debris_flow.gif">
 <img src="https://github.com/yuanming-hu/public_files/raw/master/graphics/mls-mpm-cpic/sand-sweep.gif"> <img src="https://github.com/yuanming-hu/public_files/raw/master/graphics/mls-mpm-cpic/sand_stir.gif">