It must be Saint Patrick's Day: Scientists create nanoscale shamrock (w/video)

(Nanowerk News) AMBER, Ireland’s national materials science centre based in Trinity College Dublin has etched a nano sized shamrock whose stem is approximately 200,000 times smaller than a grain of salt. The shamrock, 500 of which could fit side by side on a single human hair, has been etched on to a Trinity College silver lapel pin. The pin was presented to the recipient of the SFI St Patrick’s Day Science Medal in Washington DC on March 13th at The Wild Geese Network of Irish Scientists by Professor Michael Morris, AMBER Principal Investigator.
The shamrock was etched using the AMBER Helium Ion Microscope in Trinity which is the only one in Ireland and one of only a handful in Europe. The microscope enables very high resolution imaging of less than 1 nanometre and is used to image and pattern a range of materials. AMBER researchers use the microscope to image graphene and other 2D materials, bio-engineered scaffolds for tissue engineering and a range of polymer composites for research and industry purposes.
A short video showing how the shamrock was etched:
AMBER is a partnership between world-class scientists and industry. Working in partnership with the Royal College of Surgeons in Ireland and University College Cork and based in Trinity, AMBER is funded by Science Foundation Ireland and industry partners. It is focused on translating science into new discoveries and devices for the ICT, medical devices and industrial technology sectors. Its research programmes are tackling significant industrial challenges and include the development of novel data processing and memory applications, thermoelectric devices, food and pharmaceutical packaging, medical implant coatings, diagnostics and drug delivery systems, and regenerative tissue engineering.
Source: Trinity College Dublin