Post-it note with handwritten message in blue marker. The message reads: "Rest In Peace. In your Happy Place Now."

Card made by a student from the George Washington University Hillel. Front cover reads: "We Are One" with an illustrated heart below. The inside reads: "The GW community sends prayers and holds your community in our hearts. We will find a way to come out stronger."

Square card with white and yellow text against blue background. Card reads, "Mitzvah4Pittsburgh. Some spread darkness. We spread light. Choose a good deed. Choose a Mitzvah. Add light to the world," followed by four options and a place for respondents to list their name and email address. Some names and email addresses have been redacted for privacy.

Note from a member of The Church at Severn Run in Severn, Maryland. The note is enclosed in an envelope with church letterhead, reading: "The Church at Severn Run: Love Well, Live Jesus, Believe Big!" The note inside has faded due to water damage; the remaining text reads: "Hello we would like to send some thoughts, love, and positivity during this time because you matter." The church's contact information is included on the back of the envelope.

Post-it note with handwritten message in blue marker. The message reads: "May your memory be for a blessing. Sending love and healing from Jews in Berkeley, CA." Signed with a Star of David.

Post-it note with a hand drawn illustration in red marker. An abstract heart appears in the lower center.

Note from a member of The Church at Severn Run in Severn, Maryland. The note is enclosed in an envelope with church letterhead, reading: "The Church at Severn Run: Love Well, Live Jesus, Believe Big!" The note inside reads: "We are with you, our brothers and sisters. Stand strong within your faith- unyielding, unshakeable. Do not despair." The church's contact information is included on the back of the envelope.

Note from a member of The Church at Severn Run in Severn, Maryland. The note is enclosed in an envelope with church letterhead, reading: "The Church at Severn Run: Love Well, Live Jesus, Believe Big!" The note inside reads: The church's contact information is included on the back of the envelope. "Our hearts are burdened by what happened in Pittsburgh. We know that we serve the same G-d and the G-d of the Old and New Testaments does not call us to violence each other. We pray for healing in Pittsburgh, in synagogues throughout America and for love from all churches.

Post-it note with handwritten message in blue marker. The message reads, in English and Hebrew: "Be strong, be strong and may we all be strengthened."

Note from a member of The Church at Severn Run in Severn, Maryland. The note is enclosed in an envelope with church letterhead, reading: "The Church at Severn Run: Love Well, Live Jesus, Believe Big!" The note inside reads: "My thoughts are with you. We must erase hate. I love you. B.R." The church's contact information is included on the back of the envelope.

Printed tag with a photograph of Rose Mallinger. The tag reads: "In Memory of Rose Mallinger." Creasing and staining due to exposure to the elements at the Wilkins memorial.

Zine page with bubble letters and information about the emotional value of hugs. Zine page with cartoons illustrating the emotional value of hugs, including a superhero, labeled "Hugs to the Rescue" and a young couple.

Card from a student at West Allegheny Middle School in Imperial, Pa. The front features a hand-colored illustration of the words: "Be Strong" and other floral and geometric motifs. The back contains a handwritten note, as well as the stock signature: "From your friends at West Allegheny Middle School."

Card from a student at West Allegheny Middle School in Imperial, Pa. The front features a hand-colored illustration of a bird with a leaf in its mouth with floral and geometric motifs. The back contains a handwritten note, as well as the stock signature: "From your friends at West Allegheny Middle School."

Post-it note with handwritten message in blue ink. The message reads: "We are here."

Card from a student at West Allegheny Middle School in Imperial, Pa. The front features a hand-colored illustration of a bird with a leaf in its mouth and floral and geometric motifs. The back contains a handwritten note, as well as the stock signature: "From your friends at West Allegheny Middle School."

Card from a congregant at the Holy Angels Parish. The front cover contains a stock illustration of seven children holding hands around a table with a large goblet and loaf of braided bread, and seven doves. The illustration is labeled: "We are people of God's peace." The inside reads: "Dear Tree of Life member. You are all in our thoughts and prayers. Holy Angels\CCD. Jason [last name redacted]." Due to water exposure at the memorial site, the ink on this card has partially lifted.

Post-it note with handwritten message in blue marker. The message reads: "No hate" [heart, broken heart]. Just [heart]."